Human papillomavirus-mediated expression of complement regulatory proteins in human cervical cancer cells

OBJECTIVES

This study aimed to evaluate the expression pattern of complement regulatory proteins (CRPs) CD46, CD59, and CD55 in HPV-positive (HPV+) & negative (HPV-) cervical cancer cell lines in search of a reliable differential biomarker.

STUDY DESIGN

We analysed the expression of CRPs in HPV 16-positive SiHa cell line, HPV 18-positive HeLa cell line, and HPV-negative cell line C33a using RT-qPCR, Western blotting, flow cytometry, and confocal microscopy.

RESULTS

We observed a differential expression profile of CRPs in HPV+ and HPV- cervical cancer cell lines. The mRNA level of CD59 & CD55 showed a higher expression pattern in HPV+ cells when compared to HPV- cancer cells. However, flow cytometry-based experiments revealed that CD46 was preferentially expressed more in HPV 16-positive SiHa cells followed by HPV 18-positive HeLa cells when compared to HPV- C33a cells. Interestingly, confocal microscopy revealed a high level of CD59 expression in Hela cells and SiHa cells but low expression in HPV- C33a cells. In addition, HPV 18-positive HeLa cells expressed more CD55, which was lower in SiHa cells and very weak in C33a cells.

CONCLUSION

The study demonstrates the differential expression of CRPs in both HPV+ and HPV- cervical cancer cells for the first time, and their potential to serve as an early diagnostic marker for cervical carcinogenesis.

Estrogen receptors in human bladder cells regulate innate cytokine responses to differentially modulate uropathogenic E. coli colonization

The bladder epithelial cells elicit robust innate immune responses against urinary tract infections (UTIs) for preventing the bacterial colonization. Physiological fluctuations in circulating estrogen levels in women increase the susceptibility to UTI pathogenesis, often resulting in adverse health outcomes. Dr adhesin bearing Escherichia coli (Dr E. coli) cause recurrent UTIs in menopausal women and acute pyelonephritis in pregnant women. Dr E. coli bind to epithelial cells via host innate immune receptor CD55, under hormonal influence. The role of estrogens or estrogen receptors (ERs) in regulating the innate immune responses in the bladder are poorly understood. In the current study, we investigated the role of ERα, ERβ and GPR30 in modulating the innate immune responses against Dr E. coli induced UTI using human bladder epithelial carcinoma 5637 cells (HBEC). Both ERα and ERβ agonist treatment in bladder cells induced a protection against Dr E. coli invasion via upregulation of TNFα and downregulation of CD55 and IL10, and these effects were reversed by action of ERα and ERβ antagoinsts. In contrast, the agonist-mediated activation of GPR30 led to an increased bacterial colonization due to suppression of innate immune factors in the bladder cells, and these effects were reversed by the antagonist-mediated suppression of GPR30. Further, siRNA-mediated ERα knockdown in the bladder cells reversed the protection against bacterial invasion observed in the ERα positive bladder cells, by modulating the gene expression of TNFα, CD55 and IL10, thus confirming the protective role of ERα. We demonstrate for the first time a protective role of nuclear ERs, ERα and ERβ but not of membrane ER, GPR30 against Dr E. coli invasion in HBEC 5637 cells. These findings have many clinical implications and suggest that ERs may serve as potential drug targets towards developing novel therapeutics for regulating local innate immunity and treating UTIs.

Estrogen receptor subtype agonist activation in human cutaneous squamous cell carcinoma cells modulates expression of CD55 and Cyclin D1

Clinical studies indicate gender bias in cutaneous squamous cell carcinoma (cSCC) incidence with worse prognosis observed in males than in females, suggesting estrogen-mediated protection. In contrast, recent clinical population studies show risk of cSCC by use of oral contraceptives, thus raising controversy. However, animal studies indicate a protective role of estrogen and estrogen receptor (ER)s in cSCC. Currently we have a poor understanding of ERs that are expressed in human cSCC cells and their possible role in malignant transformation. The focus of current study was to determine ER subtype specific expression on cSCC A431 cells and investigate if ER agonist based activation modulates tumor markers CD55 and Cyclin D1 in the cells. ERα, ERβ and G protein-coupled receptor (GPR30) subtype expression at mRNA and protein level was determined in human cSCC A431 cells by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting, respectively. The localization of ER subtypes was determined by confocal microscopy. ER subtype agonist based activation on A431 cells was performed to investigate their role in modulating mRNA and protein expression of tumor markers CD55 and Cyclin D1. A431 cells differentially expressed all three ER subtypes- ERα, ERβ and GPR30 with GPR30 expression being the highest. Confocal studies confirmed that all three ER subtypes were expressed in the cytoplasm and ERα and ERβ lacked nuclear expression. Agonist based activation of both ERα and GPR30 significantly upregulated Cyclin D1 and CD55 expression. Blocking of GPR30 led to significantly downregulation of both Cyclin D1 and CD55 expression. In contrast to ERα and GPR30, ERβ activation significantly downregulated CD55 expression. Taken together, here we demonstrate for the first time that all three ERs- ERα, ERβ and GPR30 are expressed in human A431 cSCC cells and further ER agonist based activation modulates the expression of tumor markers CD55 and Cyclin D1.

Estrogen receptor alpha differentially modulates host immunity in the bladder and kidney in response to urinary tract infection

The protective role of endogenous estrogen against Urinary Tract Infection (UTI) is well recognized, but the involvement of estrogen receptors (ERs) in modulating immunity in the urinary tract during UTI pathogenesis has not been investigated. The current study investigates the role of ERα in modulating immune responses and UTI outcome. Mice were pre-treated with either ERα agonist, propyl-pyrazole-triol (PPT), or ERα antagonist, methyl-piperidino-pyrazole (MPP), before experimental UTI. The UTI outcome was determined by checking the bacterial load, CD55 and TNFα expression in the bladder and kidney tissues. We observed opposite effects of PPT and MPP treatment on bacterial clearance in bladder versus kidney. PPT significantly reduced bacterial load (P < 0.05) only in the kidney, with minimal changes in CD55 and TNFα levels. In contrast, MPP showed remarkable bacterial clearance only in the bladder that corresponded with reduced CD55 and TNFα expression. MPP treatment in uninfected state induced a significant increase in TNFα production (P < 0.05) in the bladder, but not in the kidney. Our results suggest a protective role of ERα in the kidney. However, protection in the bladder may be mediated via other ER subtypes that may be involved in boosting the local immune responses. Drugs targeting specific ERs in bladder may serve as an adjunct treatment for boosting immune responses in the urogenital tract for efficient bacterial clearance.

Characteristics of carcinoembryonic antigen-producing colorectal cancers: A population based study

Objectives: Serum carcinoembryonic antigen is a tumor marker often found to be elevated in colorectal cancer patients. Elevated carcinoembryonic antigen has been strongly associated with poor prognosis. However, little is known about the patient and tumor characteristics between carcinoembryonic antigen-secreting and non-secreting tumors. Methods: We performed a retrospective analysis of all patients (N=164,187) in the Surveillance, Epidemiology and End Results database diagnosed with colorectal adenocarcinoma from 2010 to 2014. All patients were designated as having either positive/elevated (C1) or negative/normal (C0) pretreatment serum carcinoembryonic antigen level. Results: Of the 164,187 patients, 68,833 (57.0%) had available carcinoembryonic antigen information, and 33,412 (48.5%) had positive/elevated (C1) antigen levels. Median age was 65 years, and 36,464 (53.0%) were male. Patients with C1 cancers were more likely to be female (Odds ratio 1.06), black (Odds ratio 1.62), separated or never married (Odds ratios 1.50 and 1.49, respectively), higher grade (Odds ratios 1.35, 1.64, and 1.72 of moderately, poorly, and undifferentiated cancers, respectively), and of signet ring cell histology (Odds ratio 1.47) compared to males, whites, married participants, well differentiated grade, and adenocarcinoma histology respectively (P<0.001). Multivariate analysis showed that non-Caucasian race, female gender, unmarried status, distal to sigmoid colon location, increasing tumor invasion beyond muscular layer, increasing nodal involvement, and presence of metastases were independent factors associated with the C1 diagnosis. Conclusions: About half of all colorectal adenocarcinomas are associated with elevated pre-treatment serum carcinoembryonic antigen levels. Our study is the first nationwide population-based study quantifying the prevalence of serum carcinoembryonic antigen elevation in the colorectal cancer population, and identifying patient and tumor characteristics associated with elevated carcinoembryonic antigen.

Nanodiamonds facilitate killing of intracellular uropathogenic E. coli in an in vitro model of urinary tract infection pathogenesis

About 25–44% of women will experience at least one episode of recurrent UTI and the causative agent in over 70% of UTI cases is uropathogenic Escherichia coli (UPEC). UPEC cause recurrent UTI by evading the bladder’s innate immune system through internalization into the bladder epithelium where antibiotics cannot reach or be effective. Thus, it is important to develop novel therapeutics to eliminate these intracellular pathogens. Nanodiamonds (NDs) are biocompatible nanomaterials that serve as promising candidates for targeted therapeutic applications. The objective of the current study was to investigate if 6 or 25 nm NDs can kill extracellular and intracellular UPEC in infected bladder cells. We utilized the human bladder epithelial cell line, T24, and an invasive strain of UPEC that causes recurrent UTI. We found that acid-purified 6 nm NDs displayed greater antibacterial properties towards UPEC than 25 nm NDs (11.5% vs 94.2% CFU/mL at 100 μg/mL of 6 and 25 nm, respectively; P<0.001). Furthermore, 6 nm NDs were better than 25 nm NDs in reducing the number of UPEC internalized in T24 bladder cells (46.1% vs 81.1% CFU/mL at 100 μg/mL of 6 and 25 nm, respectively; P<0.01). Our studies demonstrate that 6 nm NDs interacted with T24 bladder cells in a dose-dependent manner and were internalized in 2 hours through an actin-dependent mechanism. Finally, internalization of NDs was required for reducing the number of intracellular UPEC in T24 bladder cells. These findings suggest that 6 nm NDs are promising candidates to treat recurrent UTIs.

Estrogen receptor expression in chronic hepatitis C and hepatocellular carcinoma pathogenesis

AIM

To investigate gender-specific liver estrogen receptor (ER) expression in normal subjects and patients with hepatitis C virus (HCV)-related cirrhosis and hepatocellular carcinoma (HCC).

METHODS

Liver tissues from normal donors and patients diagnosed with HCV-related cirrhosis and HCV-related HCC were obtained from the NIH Liver Tissue and Cell Distribution System. The expression of ER subtypes, ERα and ERβ, were evaluated by Western blotting and real-time RT-PCR. The subcellular distribution of ERα and ERβ was further determined in nuclear and cytoplasmic tissue lysates along with the expression of inflammatory [activated NF-κB and IκB-kinase (IKK)] and oncogenic (cyclin D1) markers by Western blotting and immunohistochemistry. The expression of ERα and ERβ was correlated with the expression of activated NF-κB, activated IKK and cyclin D1 by Spearman’s correlation.

RESULTS

Both ER subtypes were expressed in normal livers but male livers showed significantly higher expression of ERα than females (P < 0.05). We observed significantly higher mRNA expression of ERα in HCV-related HCC liver tissues as compared to normals (P < 0.05) and ERβ in livers of HCV-related cirrhosis and HCV-related HCC subjects (P < 0.05). At the protein level, there was a significantly higher expression of nuclear ERα in livers of HCV-related HCC patients and nuclear ERβ in HCV-related cirrhosis patients as compared to normals (P < 0.05). Furthermore, we observed a significantly higher expression of phosphorylated NF-κB and cyclin D1 in diseased livers (P < 0.05). There was a positive correlation between the expression of nuclear ER subtypes and nuclear cyclin D1 and a negative correlation between cytoplasmic ER subtypes and cytoplasmic phosphorylated IKK in HCV-related HCC livers. These findings suggest that dysregulated expression of ER subtypes following chronic HCV-infection may contribute to the progression of HCV-related cirrhosis to HCV-related HCC.

CONCLUSION

Gender differences were observed in ERα expression in normal livers. Alterations in ER subtype expression observed in diseased livers may influence gender-related disparity in HCV-related pathogenesis.

Purification and functionalization of nanodiamond to serve as a platform for amoxicillin delivery

Urinary tract infections (UTIs) cost $0.4-0.5 billion a year in the US and is the second most common disease affecting millions of people. As resistance to antibiotics becomes more common, a greater need for alternative treatments is needed. Nanodiamond particles (NDPs) are actively researched as drug delivery platforms due to their biocompatibility, particle size, and stable inert core. This research is aimed at developing NDPs as antibiotic drug delivery platforms for treating UTIs. To this end, 100 nm, 75 nm, 25 nm and 6 nm size NDPs are purified with acid and heat treatment techniques. Raman spectra of the NDPs showed that the acid treatment method resulted in higher diamond yield. Fourier transform infrared spectroscopy (FTIR) studies showed that both purification techniques result in oxygen terminated surface groups. Efficiency of loading amoxicillin on 25 nm NDPs based on electrostatic interaction of NDPs, functionalizing surfaces of NDPs with hydrogen, and polyethylenimine (PEI) are investigated. It is found that the electrostatic and surface hydrogenation approaches are not efficient in loading amoxicillin on the NDPs. On the other hand, PEI functionalized NDPs produced successful loading with amoxicillin as indicated by the presence of the β-lactam peak at 1770 cm(-1), amide peak at 1680 cm(-1), and bond between PEI NH stretching and amoxicillin -COOH group at 3650 cm(-1) by the FTIR spectra. These results are expected to lay the foundation for developing NDP based targeted drug delivery treatment techniques for treating UTIs and other infectious diseases.

Inorganic mercury exposure in prairie voles (Microtus ochrogaster) alters the expression of toll-like receptor 4 and activates inflammatory pathways in the liver in a sex-specific manner

Environmental exposure to mercury can cause a number of adverse effects in humans including the disruption of endocrine function that may result in sex-specific effects. The present study was designed to characterize sex-specific effects of chronic inorganic mercury exposure on toll-like receptor (TLR) 2 and TLR4 and inflammatory signaling in the liver of prairie voles (Microtus ochrogaster). Following 10 weeks of exposure to mercury via drinking water, effects on protein expression levels of TLR2 and TLR4 and the downstream p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa (NF-κB) signaling pathways were assessed. Using immunoblot analysis, we found that mercury exposure significantly enhanced the expression of TLR4 and activated p38 MAPK and NF-κB pathways in vole livers. This is the first report indicating that TLR4 may serve as a sensor for chronic mercury exposure in the liver. Further, compared to females, mercury-treated male voles exhibited significant increases in activated p38 MAPK and a greater extent of liver damage. Together, these findings establish sex-specific liver immunomodulation and cellular signaling following chronic inorganic mercury exposure. Furthermore, this study also supports the use of voles as biomarkers of environmental mercury contamination and offers a promising in vivo tool to test various therapeutic strategies for mercury detoxification.

Status of bacterial colonization, Toll-like receptor expression and nuclear factor-kappa B activation in normal and diseased human livers

Epidemiological data on bacterial translocation (BT), colonization and inflammation in normal human livers is lacking. In this study we investigated the status of bacterial colonization and inflammation in the normal, cirrhotic primary biliary cirrhosis (PBC), and nonalcoholic steatohepatitis (NASH) human liver tissues. Comparatively normal livers showed increased bacterial colonization than PBC and NASH. We analyzed mRNA levels of Toll-like receptors (TLR) 2 and TLR4, and protein levels of TLR4. Phosphorylated IKKα (pIKKα) protein estimation served as a marker for nuclear factor-kappa B (NF-κB) activation. In spite of the increased bacterial colonization in normal liver tissues, lower levels of TLR2/4 mRNA and TLR4 and pIKKα proteins were found compared to PBC and NASH indicating the maintenance of suppressed inflammation and immune tolerance in normal livers. To our knowledge, this is the first clinical evidence showing suppressed inflammation despite bacterial colonization in normal human livers thus maintaining liver immune homeostasis.

Role of sex steroid receptors in pathobiology of hepatocellular carcinoma

The striking gender disparity observed in the incidence of hepatocellular carcinoma (HCC) suggests an important role of sex hormones in HCC pathogenesis. Though the studies began as early as in 1980s, the precise role of sex hormones and the significance of their receptors in HCC still remain poorly understood and perhaps contribute to current controversies about the potential use of hormonal therapy in HCC. A comprehensive review of the existing literature revealed several shortcomings associated with the studies on estrogen receptor (ER) and androgen receptor (AR) in normal liver and HCC. These shortcomings include the use of less sensitive receptor ligand binding assays and immunohistochemistry studies for ERα alone until 1996 when ERβ isoform was identified. The animal models of HCC utilized for studies were primarily based on chemical-induced hepatocarcinogenesis with less similarity to virus-induced HCC pathogenesis. However, recent in vitro studies in hepatoma cells provide newer insights for hormonal regulation of key cellular processes including interaction of ER and AR with viral proteins. In light of the above facts, there is an urgent need for a detailed investigation of sex hormones and their receptors in normal liver and HCC. In this review, we systematically present the information currently available on androgens, estrogens and their receptors in normal liver and HCC obtained from in vitro, in vivo experimental models and clinical studies. This information will direct future basic and clinical research to bridge the gap in knowledge to explore the therapeutic potential of hormonal therapy in HCC.

A comparative review of HLA associations with hepatitis B and C viral infections across global populations

Hepatitis B (HBV) and hepatitis C (HCV) viral infection or co-infection leads to risk of development of chronic infection, cirrhosis and hepatocellular carcinoma (HCC). Immigration and globalization have added to the challenges of public health concerns regarding chronic HBV and HCV infections worldwide. The aim of this study is to review existing global literature across ethnic populations on HBV and HCV related human leukocyte antigen (HLA) associations in relation to susceptibility, viral persistence and treatment. Extensive literature search was conducted to explore the HLA associations in HBV and HCV infections reported across global populations over the past decade to understand the knowledge status, weaknesses and strengths of this information in different ethnic populations. HLA DR13 is consistently associated with HBV clearance globally. HLADRB1*11/*12 alleles and DQB1*0301 are associated with HBV persistence but with HCV clearance worldwide. Consistent association of DRB1*03 and *07 is observed with HCV susceptibility and non-responsiveness to HBV vaccination across the population. HLA DR13 is protective for vertical HBV and HCV transmission in Chinese and Italian neonates, but different alleles are associated with their susceptibility in these populations. HLA class I molecule interactions with Killer cell immunoglobulin like receptors (KIR) of natural killer (NK) cells modulate HCV infection outcome via regulating immune regulatory cells and molecules. HLA associations with HBV vaccination, interferon therapy in HBV and HCV, and with extra hepatic manifestations of viral hepatitis are also discussed. Systematic studies in compliance with global regulatory standards are required to identify the HLA specific viral epitope, stage specific T cell populations interacting with different HLA alleles during disease progression and viral clearance of chronic HBV or HCV infections among different ethnic populations. These studies would facilitate stage specific therapeutic strategies for clearance of HBV and HCV infections or co-infections across global populations and aid in identification of HBV-HCV combined vaccine. HLA associations of chronic HBV or HCV development with confounding host factors including alcohol, drug abuse, insulin resistance, age and gender are lacking and warrant detailed investigation across global populations.

Cancer-associated molecular signature in the tissue samples of patients with cirrhosis

Several types of aggressive cancers, including hepatocellular carcinoma (HCC), often arise as a multifocal primary tumor. This suggests a high rate of premalignant changes in noncancerous tissue before the formation of a solitary tumor. Examination of the messenger RNA expression profiles of tissue samples derived from patients with cirrhosis of various etiologies by complementary DNA (cDNA) microarray indicated that they can be grossly separated into two main groups. One group included hepatitis B and C virus infections, hemochromatosis, and Wilson's disease. The other group contained mainly alcoholic liver disease, autoimmune hepatitis, and primary biliary cirrhosis. Analysis of these two groups by the cross-validated leave-one-out machine-learning algorithms revealed a molecular signature containing 556 discriminative genes (P <.001). It is noteworthy that 273 genes in this signature (49%) were also significantly altered in HCC (P <.001). Many genes were previously known to be related to HCC. The 273-gene signature was validated as cancer-associated genes by matching this set to additional independent tumor tissue samples from 163 patients with HCC, 56 patients with lung carcinoma, and 38 patients with breast carcinoma. From this signature, 30 genes were altered most significantly in tissue samples from high-risk individuals with cirrhosis and from patients with HCC. Among them, 12 genes encoded secretory proteins found in sera. In conclusion, we identified a unique gene signature in the tissue samples of patients with cirrhosis, which may be used as candidate markers for diagnosing the early onset of HCC in high-risk populations and may guide new strategies for chemoprevention. Supplementary material for this article can be found on the HEPATOLOGY website (http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).

Differential expression of intestinal trefoil factor in biliary epithelial cells of primary biliary cirrhosis

Intestinal trefoil factor (ITF) promotes epithelial cell migration and mucosal restitution during inflammation. We used real-time quantitative PCR, in situ nucleic acid hybridization, and immunohistochemistry to study the expression of the ITF gene and protein expression in the liver of primary biliary cirrhosis (PBC) and controls. There were significantly higher levels of ITF messenger RNA (mRNA) in PBC liver compared with primary sclerosing cholangitis (PSC) (P <.05) or normal controls (P <.001) and also higher in hepatitis C virus (HCV) liver (P <.05) and cryptogenic cirrhosis (P <.01) compared with normal controls. However, only in PBC was there a significant difference between small (interlobular and bile ductules) and large (intrahepatic and septal) bile ducts. Using in situ hybridization, the highest levels of ITF gene expression were localized to the large bile ducts in PBC. This differential expression of ITF was also noted at the protein level. Thus, in PBC, although 92% of large bile ducts expressed the ITF protein, only 2% of small bile ducts (P <.0001) expressed ITF. In contrast, in control livers, 34% of large bile ducts and 13% of small bile ducts expressed ITF. ITF protein is absent in small bile ducts in all stages of PBC. In conclusion, the expression of ITF may play an important role in bile duct damage. In small bile ducts, ITF production in response to damage is absent, making such cells vulnerable to damage and providing a thesis for the selective loss of small, but not large, bile ducts in PBC.

Expression of complement regulatory proteins-CD 35, CD 46, CD 55, and CD 59-in benign and malignant endometrial tissue

OBJECTIVE

Complement system plays an important role in host defense mechanisms against microorganisms and tumor cells. To protect themselves from autologous complement-mediated damage, normal host tissues express cell membrane-associated complement regulatory proteins (CRPs). To investigate whether neoplastic endometrial tissues overexpress these proteins to escape complement damage, we examined the distribution of complement receptor type 1 (CR1, CD35), membrane cofactor protein (MCP, CD46), decay-accelerating factor (DAF, CD55), and protectin (MACIF, CD59) on frozen endometrial tissue samples.

METHODS

A total of 54 endometrial tissue samples were collected. Cryosections were obtained of 31 benign and 23 malignant tissue specimens. Tissue sections were stained by immunohistochemical staining procedure using specific antibodies and employing the avidin-biotin technique. Quantitation of the protein content of these CRPs was determined using the Samba 4000 image analysis system.

RESULTS

For all four of the CRPs studied, a statistically significant difference in protein expression between the benign and malignant endometrial tissue specimens (P < 0.0001) was observed.

CONCLUSIONS

Overexpression of all the CRPs studied (CD35, CD46, CD55, CD59) was observed in the malignant as compared with the benign endometrial tissues. The upregulation of these CRPs may promote resistance of the endometrial malignant tissue to complement-mediated damage, thereby allowing the tumor cells to escape from cytolysis and thus promoting carcinogenesis.

Experimental gestational pyelonephritis induces preterm births and low birth weights in C3H/HeJ mice

Urinary tract infections (UTIs) are associated with approximately 27% of premature births. Escherichia coli is the most frequent causal agent of UTIs and expresses virulence factors, including surface adhesins that recognize specific host tissue receptors. We have reported that E. coli Dr adhesin recognizes decay-accelerating factor as the host tissue receptor and that these receptors are increased during pregnancy. Induction of pathogenesis is a cumulative effect of the host-pathogen relationship involving specific host factors and virulence characteristics of the invading organism. Recently, an experimental model of chronic pyelonephritis has been developed with E. coli bearing Dr adhesin (E. coli Dr(+)) in nonpregnant lipopolysaccharide hyporesponder C3H/HeJ mice. In this study, we investigated the role of E. coli Dr(+) on the outcome of pregnancy in C3H/HeJ mice. Groups of pregnant mice were infected with E. coli Dr(+) or its isogenic mutant which does not bear the Dr adhesin (E. coli Dr(-)) by urethral catheterization. Nearly 90% of pregnant mice infected with E. coli Dr(+) delivered preterm (before 90% gestation) compared to 10% of mice infected with E. coli Dr(-) and none of the mice treated with phosphate-buffered saline (PBS). Also, there was a significant reduction in fetal birth weight in the E. coli Dr(+)-infected group compared to the E. coli Dr(-)- and PBS-treated groups (P = 0.003). This experimental model of E. coli Dr(+)-induced preterm delivery in mice may help in understanding the molecular mechanisms involved in UTI-induced preterm labor involving bacterial adhesins.

Experimental autoimmune myasthenia gravis in B10.BV8S2 transgenic mice: preferential usage of TCRAV1 gene by lymphocytes responding to acetylcholine receptor

Multiple TCRBV genes have been implicated in experimental autoimmune myasthenia gravis (EAMG) pathogenesis in susceptible H-2(b) strains of mice. We studied the contribution of specific TCRBV and AV genes in EAMG pathogenesis using B10.BV8S2 transgenic mice (H-2[b]). The TCR transgenic mice predominantly have TCRBV8S2 transgene, but can use any of the endogenous AV gene repertoire. The transgenic mice were immunized with acetylcholine receptor (AChR) in CFA and evaluated for EAMG pathogenesis. Although the lymphocyte responses to AChR in B10.BV8S2 transgenic and nontransgenic TCR wild-type mice were equivalent, a marked reduction in lymphocyte response to the dominant AChR alpha chain peptide 146-162 was observed in the TCR transgenic mice. After boosting with AChR in CFA, anti-AChR Abs were detected in the serum, and 14 of 42 (33%) of the TCR transgenic mice developed clinical EAMG. Furthermore, EAMG in TCR transgenic mice was prevented by treatment with mAb to TCRBV8, which depleted BV8-expressing T cells. Cloning and sequencing of TCRAV genes from AChR-reactive T cells from B10.BV8S2 transgenic mice revealed a pattern of restricted TCRAV gene usage. The majority (60%) of the clones sequenced showed a sequence identical with that of the TCRAV1S8 gene. In the normal spleen cells of TCR transgenic mice, AV gene usage was more random. Thus, despite the presence of a complete endogenous TCRAV repertoire in B10.BV8S2 transgenic mice, T cells responding to AChR preferentially used a single endogenous TCRAV gene, thus implicating the involvement of the TCRAV1S8 gene in EAMG pathogenesis.

TCR gene usage in experimental autoimmune myasthenia gravis pathogenesis. Usage of multiple TCRBV genes in the H-2b strains

Experimental autoimmune myasthenia gravis (EAMG) is an Ab-mediated autoimmune disease. The pathogenic auto-antibody production depends on the activation of CD4+ cells after their TCR interact with dominant T cell epitopes within acetylcholine receptor (AChR) in the context of the MHC class II molecule. In vitro analysis suggested that the TCRBV6 was the predominant TCR that recognized AChR and one of the dominant epitopes, alpha 146-162, in C57BL6 (B6, H-2b) mice. However, in vivo depletion of TCRBV6 cells in H-2b mice by anti-TCRBV6 mAb neither suppressed the in vitro immune response to AChR nor prevented development of EAMG. Moreover, B10.TCRc (H-2b) strain with a genomic deletion of TCRBV genes including TCRBV6, and B10.V beta 8.2 transgenic mice with a restricted TCRBV8S2 T cell repertoire, responded to AChR, alpha 146-162, and developed EAMG after immunizations with AChR/CFA. These data suggest that more than one TCRBV-bearing cell having the affinity for AChR-dominant peptides is involved in pathogenesis. Therefore, depletion of a single TCRBV (e.g., TCRBV6) with mAb may not be sufficient to completely suppress the response to AChR and development of EAMG. However, if a similar amino acid sequence in the TCR-VDJ (e.g., CDR3) region among different TCRBV gene(s) could be involved in recognizing the dominant AChR epitope(s), then motif-specific mAb reactive to the common motif within the VDJ region of different TCR could be used to eliminate the T cell clones involved in EAMG.

Human recombinant IL-2 augments immunoglobulin and induces rheumatoid factor production by rheumatoid arthritis lymphocytes engrafted into severe combined immunodeficient mice

Recombinant (r) human IL-2 was administered in vivo to improve homing and engraftment of rheumatoid arthritis (RA) patients' peripheral blood mononuclear cells (PBMC) into severe combined immunodeficient (SCID) mice. Human rIL-2 treatment resulted in augmented human Ig production and induced IgM rheumatoid factor (RF) of human origin in SCID-RA chimeras. The increment of human serum IgG in SCID-RA chimeras after IL-2 treatment ranged between 15 and 43% and for IgM between 50 and 98% during 2-8 weeks postengraftment. Human IgM-RF was detectable after 1 to 2 weeks after engraftment and persisted over a period of 10-13 weeks. No RF was produced in SCID mice engrafted with PBMC from healthy individuals with or without exogenous rIL-2 administration. Thus, human rIL-2 expanded autoreactive clones involved in the production of RF in the SCID-RA chimeras. The present study provides a novel approach to establish an in vivo SCID-RA model to study the cellular and molecular mechanisms involved in the production of RF and development of a RA-like lesion.

Effect of MHC class I and CD8 cell deficiency on experimental autoimmune myasthenia gravis pathogenesis

MHC class I and CD8+ cell deficiency have either prevented systemic lupus erythematosus-like disease in mice or enhanced type I diabetes in nonobese diabetic mice. To study the involvement of MHC class I and class I-restricted CD8+ T cells in the induction of a classical Ab-mediated disease, experimental autoimmune myasthenia gravis (EAMG), we immunized beta 2 microglobulin (beta 2-m) gene-disrupted (beta 2 m-/-) C57BL10 (B10) mice, deficient in class I gene expression and CD8+ cells, and heterozygous (beta 2-m+/-) B10 mice with normal expression of class I molecules and sufficient CD8+ cells with Torpedo acetylcholine receptor in CFA, and assessed them for clinical and immunopathologic manifestations of EAMG. Despite MHC class I and CD8+ cell deficiency, beta 2-m-/- mice developed EAMG. Moreover, the incidence of EAMG in the beta 2-m-/- mice was higher than that of beta 2-m+/- heterozygous mice with normal class I expression and frequency of CD8+ cells. The finding provided direct genetic evidence against a pathogenic effector role in C57BL10 mice for MHC class I molecule and class I-restricted CD8+ T cells in EAMG pathogenesis.

Major histocompatibility complex class II gene disruption prevents experimental autoimmune myasthenia gravis

To analyze the impact of lack of MHC class II gene expression, and to demonstrate the direct genetic evidence for the involvement of the MHC class II gene product in the development of experimental autoimmune myasthenia gravis (EAMG), MHC class II gene-disrupted C57BL6 mutant (-/-) and EAMG-susceptible MHC class II wild-type C57BL6 mice (+/+) were evaluated for the clinical and immunopathologic manifestations of EAMG. The deficiency of MHC class II, and therefore, CD4+ T cells, completely prevented the C57BL6 MHC class II mutant (-/-) mice from mounting an autoimmune response to the nicotinic acetylcholine receptor. Further, the mutant (-/-) mice failed to show any immunopathologic and clinical manifestations of EAMG. The data unequivocally provide direct genetic evidence for the essential role of MHC class II molecules in the induction of EAMG, and rule out any pathogenic effector role for MHC class I-restricted CD8+ T cells, gamma delta TCR-bearing cells, or NK cells, which are intact in the MHC class II mutant mice in the induction of EAMG.

HLA-linked susceptibility to rheumatoid arthritis in north India

Nine multiplex RA families of North Indian origin were tissue typed to determine the segregation of parental haplotypes among sibs. The assortment of haplotypes in 18 affected sibs was not random, with seven sib pairs being HLA identical and two haploidentical with the proband (P = 0.0007). HLA-DR4 occurred in eight out of nine probands (88.8%) and in 11 out of 13 familial RA subjects (84.6%).