Resident CD4+ {alpha}{beta} T cells of the murine female genital tract: a phenotypically distinct T cell lineage that rapidly proliferates in response to systemic T cell activation stimuli

A population of CD4⁺ cells has been identified in the murinefemale genital tract (FGT). Phenotypic studies of FGT CD4⁺ cellsdemonstrate that they express CD3 and that the majority of thesecells are ßTCR⁺Thy-1⁺. Most of the Thy-1⁺CD4⁺ßTCR⁺ cells resemble memory T cells based on their expressionof CD44, L-selectin and CD45RB antigens. The vast majority ofThy-1⁺CD4⁺ßTCR⁺ FGT cells are CD5⁺ and all of themare B220^–. Systemic stimuli including infection with Trypanosomabrucel brucel, injection with anti-CD3, or bacterial superantigensstaphylococcal enterotoxin A or B cause a rapid accumulationof CD4+cells in the FGT exceeding that observed for CD4⁺ cellsin spleen and lymph nodes (LN). Expansion of the FGT CD4⁺ cells,which are phenotypically distinct from the splenic and LN CD4⁺T cells, is due to local proliferation rather than an influxof cells from the circulation. The CD4⁺ population in the FGTof adult nu/nu mice is dramatically reduced, indicating itsthymic dependency. In lpr/lpr mice, FGT CD4 cells do not displaychanges characteristic of splenic or LN CD4 cells in the sameanimals. These findings demonstrate that the CD4⁺ cells of themurine FGT are thymic dependent, but that they constitute aT cell lineage that phenotypically and, probably functionally,is distinct from other peripheral CD4⁺ T cell populations.     

Effective mucosal immunization against respiratory syncytial virus using purified F protein and a genetically detoxified cholera holotoxin, CT-E29H

We exploited the powerful adjuvant properties of cholera holotoxin (CT) to create a mucosally administered subunit vaccine against respiratory syncytial virus (RSV). A genetically detoxified mutant CT with an E to H substitution at amino acid 29 of the CT-A1 subunit (CT-E29H) was compared to wild type CT for toxicity and potential use as an intranasal (IN) adjuvant for the natural fusion (F) protein of RSV. When compared to CT the results demonstrated that: (1) CT-E29H binding to GM1 ganglioside was equivalent, (2) ADP-ribosylation of agmatine was 11.7%, and (3) toxicity was attenuated in both Y-1 adrenal (1.2%) and patent mouse gut weight assays. IN vaccination with F protein formulated with CT-E29H induced serum anti-CT and anti-F protein antibodies that were comparable to those obtained after vaccination with equivalent doses of CT. Vaccinations containing CT-E29H at doses of 0.1 microg were statistically equivalent to 1.0 microg in enhancing responses to F protein. Antigen-specific mucosal IgA and anti-RSV neutralizing antibodies were detected in nasal washes and sera, respectively, of mice that had received F protein and 0.1 or 1.0 microg of CT-E29H. Anti-F protein IgA was not detected in the nasal washes from mice IN vaccinated with 0.01 microg CT-E29H or IM with F protein adsorbed to AlOH adjuvant. In addition, the formulation of purified F protein and CT-E29H (0.1 and 1.0 microg) facilitated protection of both mouse lung and nose from live RSV challenge. Collectively, the data have important implications for vaccine strategies that use genetically detoxified mutant cholera holotoxins for the mucosal delivery of highly purified RSV antigens.     

Interaction of heavy and light chains of myeloma immunoglobulin with pooled normal chains: quantitative analysis of association and restoration of idiotype

We have analyzed in vitro recombinants between the isolated heavy (H) or light (L) chains of mouse myeloma protein MOPC-21 and L or H chains of normal mouse serum immunoglobulin (Ig). In the first series of experiments using fixed H chain and solubilized L chain, we have found out that only about 30% of normal L chain pool interact efficiently with individual H chain. Moreover, fractions with different affinity to H-MOPC-21 appeared to exist among normal L chains. In the second set of experiments recombination of H and L chains in solution was used. Examination of recombinants between myeloma H chain and normal L chains revealed a set representing 6% of L chain repertoire capable of forming MOPC-21-like idiotypic structure.     

Recombinant ST2 boosts hepatic Th2 response in vivo

Excessive scarring or fibrosis is a common feature of a wide spectrum of diseases characterized by an exaggerated Th2 response. The TLR/IL-1 receptor (IL-1R)-related protein ST2 is expressed in a membrane-bound form selectively by Th2 cells and was shown to be indispensable for some in vivo Th2 responses. ST2 was also found to block TLR signaling. We addressed the impact of the ST2 pathway on fibrogenesis using a mouse model of hepatic injury and fibrosis induced by carbon tetrachloride (CCl(4)). We showed that cytokine production by intrahepatic lymphocytes from CCl(4)-injured liver is abrogated in the absence of TLR-4. Interfering with the ST2 pathway using an ST2-Fc fusion protein accelerated and enhanced hepatic fibrosis, paralleled by the increasing ex vivo secretion of Th2 cytokines IL-4, -5, -10, and -13 by intrahepatic lymphocytes of ST2-Fc-treated, CCl(4)-gavaged mice. Absence of IL-4/13 signaling in IL-4Ralpha-deficient mice obliterated this ST2-Fc effect on fibrogenesis. Moreover, depletion of CD4(+) T cells abrogated ST2-Fc-enhanced Th2 cytokines and accelerated fibrosis. Thus, ST2-Fc caused overproduction of Th2 cytokines by intrahepatic CD4(+) T cells, possibly by modifying TLR-4 signaling in injured liver. This ST2-Fc-driven Th2 response exacerbated CCl(4)-induced hepatic fibrosis.     

Expression of IgA and IgM Fc receptors on murine T lymphocytes

Fc receptors are induced on T cells following activation via the TCR. T cells that express Fc receptors transiently have the ability to use two different cognate systems: the TCR and immunoglobulins bound to the Fc receptors. The studies discussed in this article are focused on the Fc alpha and Fc mu receptors that can be induced on certain subsets of murine T lymphocytes. The article emphasizes the role of the T cell receptor for antigen in the expression of Fc alpha and Fc mu receptors on murine T cells and reviews experimental observations that suggest significant molecular heterogeneity of these Fc receptors. The finding that regulation of expression of Fc alpha receptors and Fc mu receptors on T lymphocytes is linked to cellular activation via the CD3/TCR complex implies that these Fc receptors might mediate important functions in the biology and pathology of T cells.     

Allelic exclusion frequency analysis and molecular characteristics of immunoglobulins secreted by the hybridomas expressing both allelic genes

The investigation of 750 B-lymphocyte hybridoma clones obtained by fusion of mouse myeloma and newborn heterozygous Igk-1a/Igk-1b rat splenocytes has revealed that 9.8% of Ig kappa-chain loci are rearranged productively. Seventeen hybridomas secrete kappa-chains of both allelic variants. The analysis of IgM molecules of 9 such clones demonstrated that in 6 cases only one L-chain allotype, either 1a or 1b, is present in IgM. Thus for the first time the high frequency of selective association of H and L chains in Ig-producing cells was shown. Evidently this selectivity may function as one of allelic exclusion mechanisms at the Ig assembly stage.     

Attenuated liver fibrosis in the absence of B cells

Analysis of mononuclear cells in the adult mouse liver revealed that B cells represent as much as half of the intrahepatic lymphocyte population. Intrahepatic B cells (IHB cells) are phenotypically similar to splenic B2 cells but express lower levels of CD23 and CD21 and higher levels of CD5. IHB cells proliferate as well as splenic B cells in response to anti-IgM and LPS stimulation in vitro. VDJ gene rearrangements in IHB cells contain insertions of N,P region nucleotides characteristic of B cells maturing in the adult bone marrow rather than in the fetal liver. To evaluate whether B cells can have an impact on liver pathology, we compared CCl4-induced fibrosis development in B cell-deficient and wild-type mice. CCl4 caused similar acute liver injury in mutant and wild-type mice. However, following 6 weeks of CCl4 treatment, histochemical analyses showed markedly reduced collagen deposition in B cell-deficient as compared with wild-type mice. By analyzing mice that have normal numbers of B cells but lack either T cells or immunoglobulin in the serum, we established that B cells have an impact on fibrosis in an antibody- and T cell-independent manner.     

CpG containing oligodeoxynucleotides are potent adjuvants for parenteral vaccination with the fusion (F) protein of respiratory syncytial virus (RSV)

The feasibility of using oligodeoxynucleotides (ODN) containing unmethylated CpG motifs as parenteral adjuvants for subunit vaccines against RSV was tested in BALB/c mice. Compared with immunization with natural F protein adsorbed to aluminum hydroxide (F/AlOH) adjuvant alone, coadministration of F/AlOH with CpG ODN resulted in statistically significant increases in serum neutralization titers, an enhanced generation of splenic antigen-dependent killer cell precursors, and accelerated clearance of infectious virus from lungs 4 days after challenge. The statistically significant increases in serum IFNγ and anti-F protein IgG2a titers, and significantly diminished pulmonary IL-5 and eosinophilia after challenge indicated that CpG ODN enhanced the ability of F/AlOH to elicit type 1 immune responses. F protein-specific serum IgE titers were also reduced. Further analysis of pulmonary inflammatory cells demonstrated an expansion of CD8⁺ T cells, relative to the CD4⁺ T cell compartment. The potency of CpG ODN was not adversely affected in gene knockout mice devoid of the p35 chain of the IL-12 heterodimer. Taken together, the results suggest a novel formulation for naïve recipients of F protein-based subunit vaccines that does not result in a type 2 phenotype.