Use of RT-PCR in conjunction with a respiratory pathogen assay to concurrently determine the prevalence of bacteria and SARS-CoV-2 from the nasopharynx of outpatients.

Introduction: COVID-19 has emerged as a highly contagious and debilitating disease caused by the SARS-CoV-2 virus and has claimed the lives of over 7.7 million people worldwide. Bacterial co-infections are one of many co-morbidities that have been suggested to impact the outcome of COVID-19 in patients. The goals of this study are to elucidate the presence of bacteria in the nasopharynx of SARS-CoV-2 positive and negative patients and to describe demographic categories that may be associated with the detection of these organisms during one of the initial waves of the COVID-19 pandemic. Methods: To this end, we investigated SARS-CoV-2 and bacterial co-detection from outpatient RT-PCR testing in Texas. Results: The results indicate that Staphylococcus aureus, Streptococcus pneumoniae, Klebsiella pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae were the most frequently detected bacteria in both SARS-CoV-2 positive and SARS-CoV-2 negative patients and that these bacteria were present in these two patient populations at similar proportions. We also detected Staphylococcus aureus in a significantly larger proportion of males relative to females and people under 65 years of age relative to those 65 and over. Finally, we observed that SARS-CoV-2 was more commonly detected in Hispanics compared to non-Hispanics; however, low disclosure rates make volunteer bias a concern when interpreting the effects of demographic variables. Discussion: This study describes the bacteria present in the nasopharynx of SARS-CoV-2 positive and negative patients, highlights associations between patient demographics and SARS-CoV-2 as well as bacterial co-detection. In addition, this study highlights RT-PCR based molecular testing as a tool to detect bacteria simultaneously when SARS-CoV-2 tests are performed.

Raised CA19-9 and CEA have prognostic relevance in gallbladder carcinoma.

BACKGROUND: Role of tumor markers in gall bladder carcinoma (GBC) is not well established. We evaluated the prognostic value of carbohydrate antigen 19-9 (CA19-9) and carcinoma embryonic antigen (CEA) in patients with GBC. METHODS: Of the 225 patients of GBC enrolled,176 patients were included in the study (excluded 49 patients with jaundice). Patients were divided into 3 groups; resectable n = 92, unresectable n = 17, metastatic n = 67. The clinico-pathological characteristics, tumor markers and survival data were analysed. The cutoff values of CA19-9 & CEA for predicting metastases were computed using receiver operating characteristic curve. Kaplan Meir survival and Cox regression analysis were done for factors predicting survival and recurrence. RESULTS: The median value of Ca19-9 was significantly higher in metastatic group [resectable: 21.3, unresectable: 53.9 and metastatic: 79; p < 0.001] but not for CEA [3.5, 7.8 and 5 ng/ml (p = 0.20)]. A cutoff value of 72 IU/ml for CA19-9, 5 ng/ml for CEA had a sensitivity and specificity of 52 and 80%, 51 and 72% respectively for detection of metastatic disease. Median, 3-year & 5-year survival were significantly lower in patients with CEA > 4 (p = 0.041), Ca19.9 > 37 (p = 0.019), T3/T4 (p = 0.001), node positive (p = 0.001) and presence of perineural invasion (p = 0.001). However, on multivariate analysis, only Ca19.9 > 37 predicted recurrence (p = 0.002, HR 5.8). CONCLUSIONS: Raised CA19.9 and CEA predict metastatic disease in patients with GBC without jaundice with a high specificity and may help in prognostication of the patient. CA19-9 was better than CEA in prediction of tumor burden and in predicting recurrence.

Prognostic Significance of HER-2 and p53 Expression in Gallbladder Carcinoma in North Indian Patients.

BACKGROUND/OBJECTIVE: Proto-oncogenes (HER-2) and tumor suppressor genes (p53) are commonly deregulated in gallbladder cancer (GBC). Available literature discloses skewed data from endemic Asian countries, especially north India. This study evaluates the prognostic significance of HER-2 and p53 in GBC patients from two major hospitals. METHODS: Sixty resectable tumor and control specimens were prospectively collected from December 2012 to January 2016. Immunohistochemical staining was done using monoclonal antibodies to semiquantitatively evaluate HER-2 and p53 protein expression. The criterion for HER-2 positivity was set at >30% tumor cells showing complete, membranous staining while p53 positivity was established at <50% tumor cells showing complete nuclear staining. Clinicopathological correlations were drawn with major clinical outcomes. RESULTS: It was observed that 36.67% (22/60) tumor cases and 5% (3/60) control cases showed strong HER-2 overexpression significantly correlating with sex, T-stage, nodal spread and distant metastasis (p < 0.05), while 33.3% (20/60) positivity was observed for p53 in tumor cases and 1.7% (1/60) in control cases. Multivariate analysis showed HER-2 (p = 0.04; hazard ratio: 2.36; 95% confidence interval: 1.04-5.33) and p53 (p = 0.03; hazard ratio: 5.63; 95% confidence interval: 1.21-26.26) expression to be independent prognostic factors. CONCLUSION: Our study thus suggests the plausible role of HER-2 and p53 expression in worse prognosis of GBC in a north Indian population.

Reduced Leukocyte Infiltration in Absence of Eosinophils Correlates with Decreased Tissue Damage and Disease Susceptibility in ΔdblGATA Mice during Murine Neurocysticercosis.

Neurocysticercosis (NCC) is one of the most common helminth parasitic diseases of the central nervous system (CNS) and the leading cause of acquired epilepsy worldwide. NCC is caused by the presence of the metacestode larvae of the tapeworm Taenia solium within brain tissues. NCC patients exhibit a long asymptomatic phase followed by a phase of symptoms including increased intra-cranial pressure and seizures. While the asymptomatic phase is attributed to the immunosuppressive capabilities of viable T. solium parasites, release of antigens by dying organisms induce strong immune responses and associated symptoms. Previous studies in T. solium-infected pigs have shown that the inflammatory response consists of various leukocyte populations including eosinophils, macrophages, and T cells among others. Because the role of eosinophils within the brain has not been investigated during NCC, we examined parasite burden, disease susceptibility and the composition of the inflammatory reaction in the brains of infected wild type (WT) and eosinophil-deficient mice (ΔdblGATA) using a murine model of NCC in which mice were infected intracranially with Mesocestoides corti, a cestode parasite related to T. solium. In WT mice, we observed a time-dependent induction of eosinophil recruitment in infected mice, contrasting with an overall reduced leukocyte infiltration in ΔdblGATA brains. Although, ΔdblGATA mice exhibited an increased parasite burden, reduced tissue damage and less disease susceptibility was observed when compared to infected WT mice. Cellular infiltrates in infected ΔdblGATA mice were comprised of more mast cells, and αß T cells, which correlated with an abundant CD8+ T cell response and reduced CD4+ Th1 and Th2 responses. Thus, our data suggest that enhanced inflammatory response in WT mice appears detrimental and associates with increased disease susceptibility, despite the reduced parasite burden in the CNS. Overall reduced leukocyte infiltration due to absence of eosinophils correlates with attenuated tissue damage and longer survival of ΔdblGATA mice. Therefore, our study suggests that approaches to clear NCC will require strategies to tightly control the host immune response while eradicating the parasite with minimal damage to brain tissue.

Clear cell hepatocellular carcinoma: Back to the basics for diagnosis.

Hepatocellular carcinoma (HCC) is a common cancer world-wide with a higher incidence in Asia. Clear cell variant of HCC (CCHCC) has a frequency ranging from 0.4% to 37%. The presence of 90-100% clear cells is rare. In the present case, a 35-year-old female patient presented with fever and a large abdominal mass in the right hypochondrium. Histology of the tumor revealed >95% clear cells and after taking multiple sections from different areas of tumor only few scattered cells with eosinophilic cytoplasm were found. Immunohistochemistry with Hep Par 1, Glypican 3 and polyclonal carcinoembryonic antigen were negative as were all other markers for metastatic clear cell tumors. Histological diagnosis was based on routine H and E sections showing a histological pattern of architecture with thickened trabeculae. We describe a rare case of CCHCC with >95% clear cells and no immunoreactivity in tumor cells in a non-cirrhotic liver.

Leukocyte infiltration into spinal cord of EAE mice is attenuated by removal of endothelial leptin signaling.

Leptin, a pleiotropic adipokine, crosses the blood-brain barrier (BBB) and blood-spinal cord barrier (BSCB) from the periphery and facilitates experimental autoimmune encephalomyelitis (EAE). EAE induces dynamic changes of leptin receptors in enriched brain and spinal cord microvessels, leading to further questions about the potential roles of endothelial leptin signaling in EAE progression. In endothelial leptin receptor specific knockout (ELKO) mice, there were lower EAE behavioral scores in the early phase of the disorder, better preserved BSCB function shown by reduced uptake of sodium fluorescein and leukocyte infiltration into the spinal cord. Flow cytometry showed that the ELKO mutation decreased the number of CD3 and CD45 cells in the spinal cord, although immune cell profiles in peripheral organs were unchanged. Not only were CD4(+) and CD8(+) T lymphocytes reduced, there were also lower numbers of CD11b(+)Gr1(+) granulocytes in the spinal cord of ELKO mice. In enriched microvessels from the spinal cord of the ELKO mice, the decreased expression of mRNAs for a few tight junction proteins was less pronounced in ELKO than WT mice, as was the elevation of mRNA for CCL5, CXCL9, IFN-γ, and TNF-α. Altogether, ELKO mice show reduced inflammation at the level of the BSCB, less leukocyte infiltration, and better preserved tight junction protein expression and BBB function than WT mice after EAE. Although leptin concentrations were high in ELKO mice and microvascular leptin receptors show an initial elevation before inhibition during the course of EAE, removal of leptin signaling helped to reduce disease burden. We conclude that endothelial leptin signaling exacerbates BBB dysfunction to worsen EAE.

Mutational and expressional analyses of PTEN gene in colorectal cancer from Northern India.

The PTEN is a tumor-suppressor gene located on chromosome 10q23.3 and established to play key role in the varied types of cancer. To elucidate the possible effect of mutations and inactivation of PTEN gene on the occurrence and development of colorectal cancer (CRC), 223 cancer specimens were selected to probe PTEN gene mutations through the micro dissection of the genome. Polymerase chain reaction single-strand conformation polymorphism and DNA sequencing methods were applied for mutations while protein expression was evaluated by immunohistochemistry. Mutations in exons 7 and 8 of PTEN were observed in 12.5% and PTEN loss of expression was identified in 48% in CRC. In exon 7, we found the insertion of "G" resulted into the change at codon 218 from TGC to GTC leading to change in the reading frame starting downward from Cystein to Valine. In addition, the insertion of "A" in the same exon at codon 213 resulted into the change of codon CCT to CCA, which cause silent mutation. In exon 8, however, "A" is replaced by C at codon 282, but both encodes for Glycine. Statistically significant loss of PTEN expression was observed in cancerous tissue when compared with the adjacent control (P < 0.05). Furthermore, weak PTEN expression in CRC tissues were significantly associated with tumor size, depth of invasion, lymphatic invasion, lymph node metastasis, grade of differentiation, and TNM stage (P < 0.05). Our results suggested that PTEN gene mutation and loss of PTEN expression may provide valuable prognostic information to aid treatment strategies for CRC patients.

Leukocyte infiltration across the blood-spinal cord barrier is modulated by sleep fragmentation in mice with experimental autoimmune encephalomyelitis.

BACKGROUND: We have recently shown that mice with experimental autoimmune encephalomyelitis (EAE) have increased sleep fragmentation (SF) and reduced sleep efficiency, and that the extent of SF correlates with the severity of disease. It is not yet clear whether and how sleep promotes recovery from autoimmune attacks. We hypothesized that SF promotes leukocyte infiltration across the blood-spinal cord barrier, impairs immune regulation, and thus worsens EAE. METHODS: Three groups of C57 mice were studied: Resting EAE; SF EAE with the mice subjected to the SF maneuver 12 h /day during zeitgeber time (ZT) 0-12 h; and naïve controls with neither EAE nor SF. Besides monitoring of the incidence and severity of EAE, the immune profiles of leukocytes in the spinal cord as well as those in the spleen were determined. RESULTS: When analyzed 16 days after EAE induction, at which time the SF was terminated, the SF group had a greater number of CD4(+) T cells and a higher percent of CD4(+) cells among all leukocytes in the spinal cord than the resting EAE group. When allowed to recover to 28 days after EAE induction, the SF mice had lower EAE scores than the resting EAE group. EAE induced splenomegaly and an increase of Gr1(+)CD11b(+) myeloid-derived suppressor cells in the splenocytes. However, SF treatment had no additional effect on either peripheral splenocytes or granulocytes that reached the spinal cord. CONCLUSION: The SF maneuver facilitated the migration of encephalopathic lymphocytes into the spinal cord. Paradoxically, these mice had a better EAE score after cessation of SF compared with mice without SF.

Loss of astrocytic leptin signaling worsens experimental autoimmune encephalomyelitis.

Leptin is commonly thought to play a detrimental role in exacerbating experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis. Paradoxically, we show here that astrocytic leptin signaling has beneficial effects in reducing disease severity. In the astrocyte specific leptin receptor knockout (ALKO) mouse in which leptin signaling is absent in astrocytes, there were higher EAE scores (more locomotor deficits) than in the wildtype counterparts. The difference mainly occurred at a late stage of EAE when wildtype mice showed signs of recovery whereas ALKO mice continued to deteriorate. The more severe symptoms in ALKO mice coincided with more infiltrating cells in the spinal cord and perivascular brain parenchyma, more demyelination, more infiltrating CD4 cells, and a lower percent of neutrophils in the spinal cord 28 days after EAE induction. Cultured astrocytes from wildtype mice showed increased adenosine release in response to interleukin-6 and the hippocampus of wildtype mice had increased adenosine production 28 days after EAE induction, but the ALKO mutation abolished the increase in both conditions. This indicates a role of astrocytic leptin in normal gliotransmitter release and astrocyte functions. The worsening of EAE in the ALKO mice in the late stage suggests that astrocytic leptin signaling helps to clear infiltrating leukocytes and reduce autoimmune destruction of the CNS.

Saturable leptin transport across the BBB persists in EAE mice.

We have shown that mice with experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis, have upregulated leptin receptor expression in reactive astrocytes of the hippocampus, a region involved in sickness behavior. Leptin can exacerbate EAE when its serum concentration is high. Although leptin receptors in astrocytes modulate leptin transport across cultured endothelial cell monolayers, it is not known how leptin transport in EAE mice is regulated. Here, we determined brain and cervical spinal cord uptake of leptin in early and recovery stages of EAE, after either intravenous delivery or in situ brain perfusion of (125)I-leptin and the vascular marker (131)I-albumin. While increased vascular space and general blood-brain barrier (BBB) permeability after EAE were expected, the specific saturable transport system for leptin crossing the BBB also persisted. Moreover, there was upregulation of leptin transport in hippocampus and cervical spinal cord in the early stage of EAE, shown by higher leptin uptake in these regions and by competitive inhibition with coadministered excess unlabeled leptin. We conclude that EAE induced a time- and region-specific increase of leptin transport. The results provide a link between circulating leptin and enhanced leptin signaling that may play a crucial role in disease progression.

Astrocytic leptin-receptor knockout mice show partial rescue of leptin resistance in diet-induced obesity.

To determine how astrocytic leptin signaling regulates the physiological response of mice to diet-induced obesity (DIO), we performed metabolic analyses and hypothalamic leptin signaling assays on astrocytic leptin-receptor knockout (ALKO) mice in which astrocytes lack functional leptin receptor (ObR) signaling. ALKO mice and wild-type (WT) littermate controls were studied at different stages of DIO with measurement of body wt, percent fat, metabolic activity, and biochemical parameters. When fed regular chow, the ALKO mice had similar body wt, percent fat, food intake, heat dissipation, respiratory exchange ratio, and activity as their WT littermates. There was no change in blood concentrations of triglyceride, soluble leptin receptor (sObR), mRNA for leptin and uncoupling protein 1 (UCP1) in adipose tissue, and insulin sensitivity. Unexpectedly, in response to a high-fat diet the ALKO mice had attenuated hyperleptinemia and sObR, a lower level of leptin mRNA in subcutaneous fat, and a paradoxical increase in UCP1 mRNA. Thus, ALKO mice did not show the worsening of obesity that occurs with normal WT mice and the neuronal ObR mutation that results in morbid obesity. The findings are consistent with a competing, counterregulatory model between neuronal and astrocytic leptin signaling.

Upregulation of astrocytic leptin receptor in mice with experimental autoimmune encephalomyelitis.

The detrimental role of leptin in experimental autoimmune encephalomyelitis (EAE) is opposite to its neuroprotective role in other neuropathologies. We hypothesize that a shifted cellular distribution of leptin receptors underlies the differential effects of leptin. A robust increase of ObR immunoreactivity was seen along glial fibrillary acidic protein (GFAP)(+) intermediate filaments in reactive astrocytes in the hippocampus and hypothalamus of mice with EAE. Although astrocyte-specific GFAP mRNA and protein were both increased, ObRa mRNA was elevated only after resolution of EAE symptoms, and ObRb mRNA was even decreased at the peak time of symptoms of EAE. A cell type-specific action of leptin may underlie its differential effects.

Brain interleukin-15 in neuroinflammation and behavior.

Interleukin (IL)-15 is a ubiquitously expressed cytokine existing in both intracellular and secretory forms. Here we review the expression, regulation, and functions of IL15 and its receptors in the brain. IL15 receptors show robust upregulation after neuroinflammation, suggesting a major role of IL15 signaling in cerebral function. Involvement of the IL15 system in neuropsychiatric behavior is reflected by the effects of IL15, IL15Rα, and IL2Rγ deletions on neurobehavior and neurotransmitters, the effects of IL15 treatment on neuronal activity, and the potential role of IL15 in neuroplasticity/neurogenesis. The results show that IL15 modulates GABA and serotonin transmission. This may underlie deficits in mood (depressive-like behavior and decreased normal anxiety) and memory, as well as activity level, sleep, and thermoregulation. Although IL15 has only a low level of permeation across the blood-brain barrier, peripheral IL15 is able to activate multiple signaling pathways in neurons widely distributed in CNS regions. The effects of IL15 in "preventing" neuropsychiatric symptoms in normal mice implicate a potential therapeutic role of this polypeptide cytokine.

C-reactive protein increases BBB permeability: implications for obesity and neuroinflammation.

BACKGROUND/AIMS: Acute phase C-reactive protein (CRP), elevated in obesity and inflammation, is a major binding protein for leptin. It is thought that CRP contributes to leptin resistance by preventing leptin from crossing the blood-brain barrier (BBB). Here we determined how CRP interacts with the BBB and whether it deters leptin from reaching CNS targets. METHODS: BBB permeability, compartmental distribution, tracer stability, and expression of tight junction protein and inflammatory marker were determined. RESULTS: CRP was stable in blood, but did not permeate the BBB in trace amounts. However, it increased paracellular permeability at a higher dose. Agouti viable (A(vy)) mice with adult-onset obesity show higher CRP entry into the brain. CRP did not permeate hCMEC/D3 cells nor change zona occludin-1 or cyclooxygenase-2 expression. An intermediate dose of CRP had no effect on leptin transport across the BBB after co-treatment. Thus, acute interactions between CRP and leptin at the BBB level were negligible and did not explain the leptin resistance seen in obesity. CONCLUSIONS: The interactions of CRP and the BBB are a two-phase process, with increased paracellular permeability at a high dose that enables its entry into the CNS and serves to induce reactive gliosis and impair CNS function.

Mesocestoides corti intracranial infection as a murine model for neurocysticercosis.

Neurocysticercosis (NCC) is the most common parasitic disease of the central nervous system (CNS) caused by the larval form of the tapeworm Taenia solium. NCC has a long asymptomatic period with little or no inflammation, and the sequential progression to symptomatic NCC depends upon the intense inflammation associated with degeneration of larvae. The mechanisms involved in these progressive events are difficult to study in human patients. Thus it was necessary to develop an experimental model that replicated NCC. In this review, we describe studies of a murine model of NCC in terms of the release/secretion of parasite antigens, immune responses elicited within the CNS environment and subsequent pathogenesis. In particular, the kinetics of leukocyte subsets infiltrating into the brain are discussed in the context of disruption of the CNS barriers at distinct anatomical sites and the mechanisms contributing to these processes. In addition, production of various inflammatory mediators and the mechanisms involved in their induction by the Toll-like receptor signaling pathway are described. Overall, the knowledge gained from the mouse model of NCC has provided new insights for understanding the kinetics of events contributing to different stages of NCC and should aid in the formulation of more effective therapeutic approaches.

Targeted delivery of an anti-cancer agent via steroid coupled liposomes.

In the present investigation, testosterone (T) was evaluated as a targeting ligand to direct the site-specific delivery of 5-Fluorouracil (5-FU) bearing liposomes to the androgen receptor (ARs) positive tumors and other organs like prostate, brain, and testis. The testosterone was conjugated with the distearoyl phosphatidyl ethanolamine (DSPE) and then this lipid conjugate, Testosterone-DSPE (T-DSPE) was used as one of the components of the liposome. The liposomes were prepared by cast film method using T-DSPE, egg PC, and cholesterol. Further these liposomes were characterized for vesicle shape, average size, polydispersity index, drug entrapment, and in vitro drug release. It was observed that the prepared liposomes were spherical in shape with an average size of 232 +/- 21 nm and 0.181 +/- 0.064 polydispersity index. The in vitro drug release study showed 79.50 +/- 2.81 percent drug release in 24 h. In vivo performance of the developed liposomes was evaluated using organ distribution study in male albino rats. Moreover the fluorescent microscopy was also performed using 6-Carboxyfluorescein (6-CF) as a fluorescent marker. The organ distribution and fluorescent uptake studies confirm that T-DSPE coupled liposomes were effectively taken up by various ARs expressing tissues. Thus, it may be concluded that the testosterone may be used as an effective ligand for the site-specific delivery of anti-cancer agents to various ARs positive carcinomas.

Organizing mucinous ascitis masquerading as pseudomyxoma peritonei: a process possibly caused by metaplasia but not neoplasia.

Mucinous ascitis can be differentiated from the more ominous condition pseudomyxoma peritonei microscopically by the absence of epithelial cells amidst mucin pools in the former. Herein we communicate a brief report of organizing mucinous ascitis in a 34-year-old woman, with recurrent abdominal pain localized to right iliac fossa. Imaging studies were suggestive of mucocele. Conservative management, followed by appendicectomy and enbloc removal of the surrounding mucinous adhesions, was performed. Histopathology revealed chronic obliterative appendicitis, along with presence of mucin pools, mixed inflammatory cells and reactive mesothelial cells in the surrounding peri-appendiceal tissue. There was an absence of morphologically well-defined, neoplastic epithelial cells in the mucinous pool, thus excluding the diagnosis of pseudomyxoma peritonei. The problem of reactive mesothelial cells, which at places look like epithelial cells, was solved by a panel of immunohistochemistry. The localized mucinous ascitis possibly have originated from the mucinous metaplasia of the mesothelial lining cells of the peritoneum, secondary to recurrent attacks of appendicitis.

Primary isolated extramedullary plasmacytoma of colon.

BACKGROUND: Extramedullary plasmacytoma is an uncommon entity that most commonly involves nasopharynx or upper respiratory tract. Involvement of the gastrointestinal tract occurs in approximated 10% of cases. Isolated primary plasmacytoma of colon is rare and only 7 well documented cases have been reported in the literature. CASE PRESENTATION: We present a case of 42 year male who presented with diarrhea. Multiple colonic strictures were found on investigation. Colonoscopic biopsy was not helpful in making any specific diagnosis. Patient underwent subtotal colectomy. Isolated primary colonic plasmacytoma was found on histopathological examination. CONCLUSION: Plasmacytoma is known to occur in extra osseous sites. Primary colonic plasmacytoma, however, is a rare clinical entity. Primary colonic plasmacytoma may have varying clinical presentations including multiple colonic strictures that may mimic colonic tuberculosis or inflammatory bowel disease. Although these cases are rare, treating physician as well as radiologist, and pathologist should be aware of this entity.

Expression and distribution of Toll-like receptors in the brain during murine neurocysticercosis.

In a mouse model of neurocysticercosis, the expression and distribution of Toll-like receptors (TLRs) was investigated by using both gene array analyses and in situ immunofluorescence microscopy (IF). In the normal uninfected brain, mRNA of all the TLRs are constitutively expressed albeit TLR5, TLR7, TLR8 and TLR9 to a lesser extent. In these animals, however, expression of TLR1, TLR3, TLR4 and TLR9 proteins was not detected. In contrast, parasite infection increased both gene and protein level expression of all the TLRs several fold except TLR5 where only the mRNA was upregulated. Importantly, TLRs were differentially distributed among various central nervous system (CNS) cell types and infiltrating leukocytes. TLR2 was almost exclusively localized to nervous tissue cells, particularly astrocytes, while TLR1 and TLR9 proteins were essentially limited to infiltrating leukocytes. All other TLRs tested were detected in both CNS and immune cell types. Interestingly, ependymal cells and neurofilaments of the cerebellar white matter of infected mice exhibited a substantial upregulation of TLR7 and TLR8 proteins respectively. These data provide a comprehensive analysis of TLR expression in the normal and parasite infected brain and suggest a role for TLRs in the interplay of immune cells and CNS cells during infection.