Biology subjects

Kumar, P.

Publications and source records attributed to Kumar, P..

At least 199 records · Page 11Linked to original sources

bioRxiv2021

The IL-33-ILC2 pathway protects from amebic colitis

Entamoeba histolytica is a pathogenic protozoan parasite that causes intestinal colitis, diarrhea, and in some cases, liver abscess. Through transcriptomics analysis, we observed that E. histolytica infection was associated with increased expression of IL-33 mRNA in both the human and murine colon. IL-33, the IL-1 family cytokine, is released after cell injury to alert the immune system of tissue damage during infection. Treatment with recombinant IL-33 protected mice from amebic infection and colonic tissue damage; moreover, blocking IL-33 signaling made mice more susceptible to infection and weight loss. IL-33 limited the recruitment of inflammatory immune cells and decreased the pro-inflammatory cytokine IL-6 in the colon. Type 2 immune responses, which are known to be involved in tissue repair, were upregulated by IL-33 treatment during amebic infection. Interestingly, administration of IL-33 protected RAG2-/- mice but not RAG2-/-{gamma}c-/- mice, demonstrating that IL-33 mediated protection occurred in the absence of T or B cells but required the presence of innate lymphoid cells (ILCs). IL-33 induced recruitment of ILC2 but not ILC1 and ILC3 in RAG2-/- mice. Adoptive transfer of ILC2s to RAG2-/-{gamma}c-/- mice restored IL-33 mediated protection. These data reveal that the IL-33-ILC2 pathway is an important host defense mechanism against amebic colitis.

immunology↗

bioRxiv2021

Development Of Novel Multiplex PCR For Rapid Diagnosis Of Coinfected Hemo-Parasites In Cattle

A novel, rapid and specific multiplex polymerase chain reaction has been developed for the diagnosis of hemo-parasitic infection in bovine blood by three of the most common hemo-parasites. The reported method relied on the detection of the three different bovine hemoparasites isolated from red blood cells (RBCs) of cattle by conventional Giemsa stained blood smear (GSBS) and confirmed by multiplex PCR. The designed multiplex primer sets can amplify 205, 313 and 422 bp fragments of apocytochrome b, sporozoite and macroschizont 2 (spm2) and 16S rRNA gene for Babesia bigemina, Theileria annulata and Anaplasma marginale, respectively. This multiplex PCR was sensitive with the ability to detect the presence of 150 ng of genomic DNA. The primers used in this multiplex PCR also showed highly specific amplification of specific gene fragments of each respective parasite DNA without the presence of non-specific and non-target PCR products. This multiplex PCR system was used to diagnose GSBS confirmed blood samples (N=12) found infected or co-infected with hemoparasites. A comparison of the two detection methods revealed that 58.33% of specimens showed concordant diagnoses with both techniques. The specificity, positive predictive value and kappa coefficient of agreement was highest for diagnosis of B. bigemina and lowest for A. marginale. The overall Kappa coefficient for diagnosis based on GSBS for multiple pathogen compared to multiplex PCR was 0.56 slightly behind the threshold of 0.6 of agreement. Therefore, confirmation should always be made based on PCR to rule out false positive due to differences in subjective observations, stain particles and false negative due to low level of parasitaemia. The simplicity and rapidity of this specific multiplex PCR method make it suitable for large-scale epidemiological studies and for follow-up of drug treatments.

molecular biology↗

bioRxiv2021

Phenotyping the tumor-immune microenvironment (TiME) in vivo by cellular-level optical imaging reveals unique combination phenotypes with variable inflammation and endothelial anergy

Immunotherapies have shown unprecedented clinical benefits in several malignancies1-3. However, clinical responses remain variable and unpredictable, indicating the need to develop predictive platforms that can improve patient stratification4. Phenotyping of tumors into hot, altered, or cold5 based on assessment of only T-cell infiltration in static tumor biopsies provides suboptimal prediction of immunotherapy response6,7. In vivo dynamic mechanisms within the tumor microenvironment such as tumor angiogenesis and leukocyte trafficking5,8,9 also play a central role in modulating anti-tumor immunity and therefore immunotherapy response. Here, we report novel tumor immune microenvironment (TiME) phenotyping in vivo in patients with non-invasive spatially-resolved cellular-level imaging based on endogenous contrast. Investigating skin cancers as a model, with reflectance confocal microscopy (RCM) imaging10, we determined four major phenotypes with variable prevalence of vasculature (Vasc) and inflammation (Inf) features: VaschiInfhi, VaschiInflo, VascloInfhi and Vascmed/hiInflo. The VaschiInfhi phenotype correlates with high immune activation, exhaustion, and vascular signatures while VaschiInflo with endothelial anergy and immune exclusion. Automated quantification of TiME features demonstrates moderate-high accuracy and correlation with corresponding gene expression. Prospectively analyzed response to topical immunotherapy show highest response in VascloInfhi, and reveals the added value of vascular features in predicting treatment response. Our novel in vivo cellular-level imaging and phenotyping approach can potentially advance our fundamental understanding of TiME, develop robust predictors for immunotherapy outcomes and identify novel targetable pathways in future.

cancer biology↗

bioRxiv2021

RBPSpot: Learning on Appropriate Contextual Information for RBP Binding Sites Discovery

Identifying RBP binding sites and mechanistic factors determining the interactions remain a big challenge. Besides the sparse binding motifs across the RNAs, it also requires a suitable sequence context for binding. The present work describes an approach to detect RBP binding sites while using an ultra-fast BWT/FM-indexing coupled inexact k-mer spectrum search for statistically significant seeds. The seed works as an anchor to evaluate the context and binding potential using flanking region information while leveraging from Deep Feed-forward Neural Network (DNN). Contextual features based on pentamers/dinucloetides which also capture shape and structure properties appeared critical. Contextual CG distribution pattern appeared important. The developed models also got support from MD-simulation studies and the implemented software, RBPSpot, scored consistently high for the considered performance metrics including average accuracy of [~]90% across a large number of validated datasets while maintaining consistency. It clearly outperformed some recently developed tools, including some with much complex deep-learning models, during a highly comprehensive bench-marking process involving three different data-sets and more than 50 RBPs. RBPSpot, has been made freely available, covering most of the human RBPs for which sufficient CLIP-seq data is available (131 RBPs). Besides identifying RBP binding spots across RNAs in human system, it can also be used to build new models by user provided data for any species and any RBP, making it a valuable resource in the area of regulatory system studies.

bioinformatics↗

bioRxiv2021

Amyloidogenic proteins in the SARS-CoV and SARS-CoV-2 proteomes

The phenomenon of protein aggregation is associated with a wide range of human diseases. Our knowledge on the aggregation behaviour of viral proteins, however, is still rather limited. Here, we investigated this behaviour in the the SARS-CoV and SARS-CoV-2 proteomes. An initial analysis using a panel of sequence-based predictors suggested the presence of multiple aggregation-prone regions in these proteomes, and revealed an enhanced aggregation propensity in some SARS-CoV-2 proteins. We then studied the in vitro aggregation of predicted aggregation-prone SARS-CoV-2 proteins, including the signal sequence peptide and fusion peptide 1 of the spike protein, a peptide from the NSP6 protein (NSP6-p), the ORF10 protein, and the NSP11 protein. Our results show that these peptides and proteins form aggregates via a nucleation-dependent mechanism. Moreover, we demonstrated that the aggregates of NSP11 are toxic to mammalian cell cultures. These findings provide evidence about the aggregation of proteins in the SARS-CoV-2 proteome. SignificanceThe aggregation of proteins is linked with human disease in a variety of ways. In the case of viral infections, one could expect that the aberrant aggregation of viral proteins may damage the host cells, and also that viral particles may trigger the misfolding and aggregation of host proteins, resulting in damage to the host organism. Here we investigate the aggregation propensity of SARS-CoV-2 proteins and show that many of them can form aggregates that are potentially cytotoxic. In perspective, these results suggest that a better understanding of the effects of viruses on the human protein homeostasis system could help future therapeutic efforts.

biophysics↗

bioRxiv2021

A Greener Recyclable Process for Extraction of Microbial Melanin using Ionic Liquid

Conventional techniques for the extraction of the melanin encounter several disadvantages such as poor extraction efficiency, excessive use of acid and alkali, and lengthy time duration. To extract melanin in a more sustainable manner, herein suitability of an aqueous solution of quaternary ammonium hydroxide known as tetrabutylammonium hydroxide (40% w/w TBAOH in water) to extract and purify the pigment from the endophyte Streptomyces hyderabadensis 7VPT5-5R was investigated. The solvent could extract 5.54{+/-}0.03 g/L of pure melanin against 3.31{+/-} 0.02 g/L of pure melanin by conventional method from bacterial culture resulting 66% increase in the yield of the pigment. The quaternary ammonium based solvent was further recycled for 5 consecutive cycles and production of melanin with yield ranging from 5.54{+/-}0.03 g/L to 5.47{+/-} 0.02 g/L was obtained. The yield of the pigment was 38-40% higher in the recycled solvent in comparison to the melanin yield extracted by conventional method. Considering the efficiency of the solvent for effective extraction and purification of melanin and its recyclability potential, it can be considered as a sustainable solvent for the extraction of the pigments from bacterial culture. Furthermore, the developed method for extraction of melanin from microorganisms as a sustainable source would help in reducing the cost of melanin leading to its efficient utilization in diverse fields.

microbiology↗

bioRxiv2021

Live imaging of SARS-CoV-2 infection in mice reveals neutralizing antibodies require Fc function for optimal efficacy

Neutralizing antibodies (NAbs) are effective in treating COVID-19 but the mechanism of immune protection is not fully understood. Here, we applied live bioluminescence imaging (BLI) to monitor the real-time effects of NAb treatment in prophylaxis and therapy of K18-hACE2 mice intranasally infected with SARS-CoV-2-nanoluciferase. We could visualize virus spread sequentially from the nasal cavity to the lungs and thereafter systemically to various organs including the brain, which culminated in death. Highly potent NAbs from a COVID-19 convalescent subject prevented, and also effectively resolved, established infection when administered within three days. In addition to direct Fab-mediated neutralization, Fc effector interactions of NAbs with monocytes, neutrophils and natural killer cells were required to effectively dampen inflammatory responses and limit immunopathology. Our study highlights that both Fab and Fc effector functions of NAbs are essential for optimal in vivo efficacy against SARS-CoV-2.

immunology↗

bioRxiv2021

Characterization and Heterotic Grouping of Traditional Assam rice (Oryza sativa L.)

Parents of heterotic hybrids are derived from different heterotic groups with high genetic divergence. Classification of traditional Assam rice germplasm in divergent pools will be advantageous to maximize the heterosis and thereby to ensure food security. In the present investigation, a group of 60 upland rice genotypes were characterized using 53 polymorphic simple sequence repeats (SSR) markers out of 83 molecular markers. The genetic divergence study using unweighted Neighbour-joining (UNJ) method clustered the 60 genotypes into 3 major clusters. The eleven most divergent genotypes identified were crossed in half diallel fashion to determine the mid-parent and better-parent heterosis values for the objective of heterotic grouping. No correlation between heterosis and genetic distance can be attributable to the use of a subset of markers not linked to yield or concerned. In genetic distance based heterotic grouping, the intra-group hybrids were recorded a higher frequency of crosses, grain yield per plant, specific combining ability effect, mid parent heterosis, better parent heterosis and standard parent heterosis value than those of inter-group hybrids. Overall, sn extensive choice of parents with attractive traits constellation leading to increased yield of the hybrids for much better complementation must be stressed along with a substantial hereditary distance for augmentation of yield heterosis.

genomics↗

bioRxiv2021

Defining the Yeast Resistome through in vitro Evolution and Whole Genome Sequencing

In vitro evolution and whole genome analysis were used to comprehensively identify the genetic determinants of chemical resistance in the model microbe, Saccharomyces cerevisiae. Analysis of 355 curated, laboratory-evolved clones, resistant to 80 different compounds, demonstrates differences in the types of mutations that are identified in selected versus neutral evolution and reveals numerous new, compound-target interactions. Through enrichment analysis we further identify a set of 137 genes strongly associated with or conferring drug resistance as indicated by CRISPR-Cas9 engineering. The set of 25 most frequently mutated genes was enriched for transcription factors and for almost 25 percent of the compounds, resistance was mediated by one of 100 independently derived, gain-of-function, single nucleotide variants found in 170-amino-acid domains in two Zn2C6 transcription factors, YRR1 and YRM1 (p < 1x 10 -100). This remarkable enrichment for transcription factors as drug resistance genes may explain why it is challenging to develop effective antifungal killing agents and highlights their important role in evolution.

genetics↗

bioRxiv2021

Functionalized extracellular matrix scaffolds loaded with endothelial progenitor cells promote neovascularization and diabetic wound healing

Diabetic ischemic wound treatment remains a critical clinical challenge. Strategies that enhance angiogenesis and improve ischemic pathology may promote the healing of poor wounds, particularly diabetic wounds in highly ischemic condition. We previously identified a cyclic peptide LXW7 that specifically binds to integrin v{beta}3 on endothelial progenitor cells (EPCs) and endothelial cells (ECs), activates VEGF receptors, and promotes EC growth and maturation. In this study, we designed and synthesized a pro-angiogenic molecule LXW7-DS-SILY by conjugating LXW7 to a collagen-binding proteoglycan mimetic DS-SILY and further employed this novel bifunctional ligand to functionalize extracellular matrix (ECM) scaffolds, promote neovascularization and accelerate ischemic wound healing. We established a Zucker Diabetic Fatty (ZDF) rat ischemic skin flap model and found the wounds treated by LXW7-DS-SILY-functionalized ECM scaffolds, with or without EPCs, significantly improved wound healing, enhanced neovascularization and modulated collagen fibrillogenesis. These functionalized ECM scaffolds also significantly promoted EPC attachment, growth and survival in the ischemic environment. Altogether, this study provides a promising novel treatment to accelerate diabetic ischemic wound healing, thereby reducing limb amputation and mortality of diabetic patients.

bioengineering↗

bioRxiv2021

Microsecond simulation unravel the structural dynamics of SARS-CoV-2 Spike-C-terminal cytoplasmic tail (residues 1242-1273)

All available SARS-CoV-2 spike protein crystal and cryo-EM structures have shown missing electron densities for cytosolic C-terminal regions. Generally, the missing electron densities point towards the intrinsically disordered nature of the protein region. This curiosity has led us to investigate the C terminal cytosolic region of the spike glycoprotein of SARS-CoV-2 in isolation. The cytosolic regions is supposed to be from 1235-1273 residues or 1242-1273 residues depending on what prediction tool we use. Therefore, we have demonstrated the structural conformation of cytosolic region and its dynamics through computer simulations up to microsecond timescale using OPLS and CHARMM forcefields. The simulations have revealed the unstructured conformation of cytosolic region. Also, in temperature dependent replica-exchange molecular dynamics simulations it has shown its conformational dynamics. Further, we have validated our computational observations with circular dichroism (CD) spectroscopy-based experiments and found its signature spectra at 198 nm which is also adding the analysis as its intrinsically disordered nature. We believe that our findings will surely help us understand the structure-function relationship of the spike proteins cytosolic region. Graphical Abstract O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

bioinformatics↗

bioRxiv2020

Environmental Dependence of the Structure of the C-terminal Domain of the SARS-CoV-2 Envelope Protein

The SARS-CoV-2 envelope protein (E) is involved in a broad spectrum of functions in the cycle of the virus, including assembly, budding, envelope formation, and pathogenesis. To enable these activities, E is likely to be capable of changing its conformation depending on environmental cues. To investigate this issue, here we characterised the structural properties of the C-terminal domain of E (E-CTD), which has been reported to interact with host cell membranes. We first studied the conformation of the E-CTD in solution, finding characteristic features of a disordered protein. By contrast, in the presence of large unilamellar vesicles and micelles, which mimic cell membranes, the E-CTD was observed to become structured. The E-CTD was also found to display conformational changes with osmolytes. Furthermore, prolonged incubation of the E-CTD under physiological conditions resulted in amyloid-like fibril formation. Taken together, these findings indicate that the E-CTD can change its conformation depending on its environment, ranging from a disordered state, to a membrane-bound folded state, and an amyloid state. Our results thus provide insight into the structural basis of the role of E in the viral infection process. HighlightsO_LIThe E-CTD of SARS-CoV-2 is intrinsically disordered in solution C_LIO_LIThe E-CTD folds into an ordered structure in presence of membrane mimetics C_LIO_LIThe E-CTD displays conformational changes in the presence of osmolytes C_LIO_LIProlonged incubation of the E-CTD leads to its self-assembly into amyloid-like fibrils C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=174 SRC="FIGDIR/small/424646v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@a2d39aorg.highwire.dtl.DTLVardef@1f2581aorg.highwire.dtl.DTLVardef@17639eaorg.highwire.dtl.DTLVardef@d43ba1_HPS_FORMAT_FIGEXP M_FIG Structural heterogeneity of the E-CTD. The E-CTD shows a disordered secondary structure in an aqueous solution and converts into an ordered structure in the presence of membrane mimetics (neutral and negative lipids) and natural osmolytes (TMAO). Incubation at physiological condition shows typical amyloid-like fibrils. The yellow-colored structure represents a predicted structure of the E-CTD by PEP-FOLD. C_FIG

biophysics↗

bioRxiv2020

Active and machine learning-based approaches to rapidly enhance microbial chemical production

In order to make renewable fuels and chemicals from microbes, new methods are required to engineer microbes more intelligently. Computational approaches, to engineer strains for enhanced chemical production typically rely on detailed mechanistic models (e.g., kinetic/stoichiometric models of metabolism) -- requiring many experimental datasets for their parameterization--while experimental methods may require screening large mutant libraries to explore the design space for the few mutants with desired behaviors. To address these limitations, we developed an active and machine learning approach (ActiveOpt) to intelligently guide experiments to arrive at an optimal phenotype with minimal measured datasets. ActiveOpt was applied to two separate case studies to evaluate its potential to increase valine yields and neurosporene productivity in Escherichia coli. In both the cases, ActiveOpt identified the best performing strain in fewer experiments than the case studies used. This work demonstrates that machine and active learning approaches have the potential to greatly facilitate metabolic engineering efforts to rapidly achieve its objectives.

systems biology↗

bioRxiv2020

Immunodominant T-cell epitopes from the SARS-CoV-2 spike antigen reveal robust pre-existing T-cell immunity in unexposed individuals

The COVID-19 pandemic has revealed a range of disease phenotypes in infected patients with asymptomatic, mild or severe clinical outcomes, but the mechanisms that determine such variable outcomes remain unresolved. In this study, we identified immunodominant CD8 T-cell epitopes in the RBD and the non-RBD domain of the spike antigen using a novel TCR-binding algorithm. A selected pool of 11 predicted epitopes induced robust T-cell activation in unexposed donors demonstrating pre-existing CD4 and CD8 T-cell immunity to SARS-CoV-2 antigen. The T-cell reactivity to the predicted epitopes was higher than the Spike-S1 and S2 peptide pools containing 157 and 158 peptides both in unexposed donors and in convalescent patients suggesting that strong T-cell epitopes are likely to be missed when larger peptide pools are used in assays. A key finding of our study is that pre-existing T-cell immunity to SARS-CoV-2 is contributed by TCRs that recognize common viral antigens such as Influenza and CMV, even though the viral epitopes lack sequence identity to the SARS-CoV-2 epitopes. This finding is in contrast to multiple published studies in which pre-existing T-cell immunity is suggested to arise from shared epitopes between SARS-CoV-2 and other common cold-causing coronaviruses. Whether the presence of pre-existing T-cell immunity provides protection against COVID-19 or contributes to severe disease phenotype remains to be determined in a larger cohort. However, our findings raise the expectation that a significant majority of the global population is likely to have SARS-CoV-2 reactive T-cells because of prior exposure to flu and CMV viruses, in addition to common cold-causing coronaviruses.

immunology↗

bioRxiv2020

A Workflow of Integrated Resources to Catalyze Network Pharmacology Driven COVID-19 Research

MotivationIn the event of an outbreak due to an emerging pathogen, time is of the essence to contain or to mitigate the spread of the disease. Drug repositioning is one of the strategies that has the potential to deliver therapeutics relatively quickly. The SARS-CoV-2 pandemic has shown that integrating critical data resources to drive drug-repositioning studies, involving host-host, hostpathogen and drug-target interactions, remains a time-consuming effort that translates to a delay in the development and delivery of a life-saving therapy. ResultsHere, we describe a workflow we designed for a semi-automated integration of rapidly emerging datasets that can be generally adopted in a broad network pharmacology research setting. The workflow was used to construct a COVID-19 focused multimodal network that integrates 487 host-pathogen, 74,805 host-host protein and 1,265 drug-target interactions. The resultant Neo4j graph database named "Neo4COVID19" is accessible via a web interface and via API calls based on the Bolt protocol. We believe that our Neo4COVID19 database will be a valuable asset to the research community and will catalyze the discovery of therapeutics to fight COVID-19. Availabilityhttps://neo4covid19.ncats.io

systems biology↗

bioRxiv2020

An insight into SARS-CoV-2 Membrane protein interaction with Spike, Envelope, and Nucleocapsid proteins

Intraviral protein-protein interactions are crucial for replication, pathogenicity, and viral assembly. Among these, virus assembly is a critical step as it regulates the arrangements of viral structural proteins and helps in the encapsulation of genomic material. SARS-CoV-2 structural proteins play an essential role in the self-rearrangement, RNA encapsulation, and mature virus particle formation. In SARS-CoV, the membrane protein interacts with the envelope and spike protein in Endoplasmic Reticulum Golgi Intermediate Complex (ERGIC) to form an assembly in the lipid bilayer, followed by membrane-ribonucleoprotein (nucleocapsid) interaction. In this study, we tried to understand the interaction of membrane proteins interaction with envelope, spike, and nucleocapsid proteins using protein-protein docking. Further, simulation studies performed up to 100 ns to examine the stability of protein-protein complexes of Membrane-Envelope, Membrane-Spike, and Membrane-Nucleocapsid. Prime MM-GBSA showed high binding energy calculations than the docked complex. The interactions identified in our study will be of great importance, as it provides valuable insight into the protein-protein complex, which could be the potential drug targets for future studies.

bioinformatics↗

bioRxiv2020

Prediction and in vitro silencing of two lipid biosynthetic genes viz. SCD and SREBP1 in chicken using RNA interference

RNA interference is a widely used post transcriptional silencing mechanism for suppressing expression of the target gene. In the current study, five shRNA molecules each against SCD and SREBP1 genes were designed after considering the parameters like secondary structures of shRNA constructs, mRNA target regions, GC content and thermodynamic properties ({Delta}G overall, {Delta}G duplex and {Delta}G break-target) to knockdown their expression. After successful transfection of these shRNA molecules into the chicken embryonic hepatocyte culture, expression of the target genes were monitored by real time PCR. Significant reduction (P<0.05) in the expression of SCD and SREBP1 genes with minimal activation of immune response genes in hepatocytes was observed after transfecting the shRNA molecules into them. The shRNA constructs against SCD gene showed the knock down efficiency ranged from 20.4% to 74.2%. In case of shRNA constructs against SREBP1 gene, they showed knock down efficiency ranging from 26.8% to 95.85%. These results clearly demonstrated the successful down regulation of the gene expression by designed shRNA molecules against both the target genes under in vitro condition. The shRNA2 molecule for SCD gene and the shRNA1 molecule for SREBP1 gene were found as the best among all the shRNA molecules used for silencing the target genes under cell culture system. It is concluded that the shRNA molecules designed against SCD and SREBP1 genes showed potential to silence the expression of these genes under in vitro chicken embryonic hepatocyte cell culture system.

molecular biology↗

bioRxiv2020

In vivo imaging of retrovirus infection reveals a role for Siglec-1/CD169 in multiple routes of transmission

Early events in retrovirus transmission are determined by interactions between incoming viruses and frontline cells near entry sites. Despite their importance for retroviral pathogenesis, very little is known about these events. We developed a bioluminescence imaging (BLI)-guided multiscale imaging approach to study these events in vivo. Engineered murine leukemia reporter viruses allowed us to monitor individual stages of the retrovirus life cycle including virus particle flow, virus entry into cells, infection and spread for retroorbital, subcutaneous and oral routes. BLI permitted temporal tracking of orally administered retroviruses along the gastrointestinal tract as they traversed the lumen through Peyers Patch to reach the draining mesenteric sac. Importantly, capture and acquisition of lymph-, blood- and milk-borne retroviruses spanning three routes, was promoted by a common host factor, the I-type lectin CD169, expressed on sentinel macrophages. These results highlight how retroviruses co-opt the immune surveillance function of tissue resident sentinel macrophages for establishing infection.

microbiology↗