We have analyzed in vivo effects of the murine IL-4 mutant Q116D/Y119D (QY), which forms unproductive complexes with IL-4Ralpha and is an antagonist for IL-4 and IL-13 in vitro. Treatment of BALB/c mice with QY during immunization with OVA completely inhibited synthesis of OVA-specific IgE and IgG1. BALB/c-derived knockout mice lacking either IL-4 or IL-4Ralpha also did not develop specific IgE...

A family of immunoglobulin isotype-switch variants was isolated by sib selection from a murine hybridoma which produced an immunoglobulin G subclass 1 (IgG1) antibody specific for the capsular polysaccharide of Cryptococcus neoformans. Antibodies of the IgG1, IgG2a, and IgG2b isotypes had similar serotype specificity patterns in double immunodiffusion assays which used polysaccharides of the fo...

The effect of T lymphocytes on the IgM, IgG3, IgG1, IgG2b, and IgG2a responses of B lymphocytes to the type-2 T-independent antigens, trinitrophenylated (TNP)-Ficoll, and TNP-Levan, was investigated. T cell-bearing nu/+ mice were found to produce substantially higher IgG2 serum anti-TNP antibody than their athymic counterparts, and nu/nu and nu/+ IgG2a titers exhibiting more disparity than nu/n...

Cryptococcosis, caused by Cryptococcus neoformans, has been demonstrated to be controlled by T helper (Th)1 cells while Th2 cells are associated with fungal growth and dissemination. Although cryptococcal immunoreactive protein antigens were previously identified, their association with Th1 or Th2 immune responses was not provided. In mice, Th1-dependent IFN-γ induces the production of IgG2a, w...

The effects of natural and recombinant human gamma-interferon (IFN-gamma) on mouse monoclonal antibody-dependent cellular cytotoxicity (ADCC) mediated by U937 human monocytic-like cells were examined. The efficiency of mouse monoclonal antibody of different isotypes in inducing ADCC was also compared. The number of receptors for the Fc portion of immunoglobulin G (IgG) (FcR) for mouse IgG2a and...

The role of B7/CD28 costimulatory pathway in the polyclonal and specific lymphocyte activation induced by blood stages of Plasmodium chabaudi AS was investigated in CD28 gene knockout (CD28(-/-)) and C57BL/6 (CD28(+/+)) mice. Analysis of the spleen during the acute infection revealed a similar increase in T and B cell populations in both groups of mice. Moreover, CD28(-/-) mice were able to dev...

Immunohistochemical double-label technique was used to detect trypanosomal antigen in macrophages. Immunoglobulin (Ig)M as well as IgG2a monoclonal antibodies (mAb) specific for the variant surface glycoprotein (VSG) mediated phagocytosis of Trypanosoma congolense variant antigenic type (VAT) TC13 by macrophages [bone marrow-derived macrophage cell line from BALB/c (BALB.BM)] in vitro. Administ...

The IgG subclass responses to cold-adapted (ca) influenza A/Queensland/6/72 virus and purified haemagglutinin H3 was assessed in C57BL/6 and BALB/c mice. In BALB/c mice IgG2a was present as the major subclass in serum, lung and salivary secretions after two doses of ca virus. In contrast, the serum response in C57BL/6 mice was predominantly IgG1 after primary and secondary inoculations of ca vi...

Viruses are suspected but usually unproven triggering factors in autoimmunity. One favored mechanism to explain the role of viruses in the genesis of autoimmunity is molecular mimicry. An immunoinflammatory blinding lesion called herpetic stromal keratitis (HSK) that follows ocular infection with herpes simplex virus (HSV) is suggested to result from a CD4(+) T-cell response to a UL6 peptide of...

Introduction: Hepatitis C virus (HCV) infection is a major public health problem which influences about 170 million people worldwide. Different types of vaccines have been designed using HCV structural proteins to control the viral infection. The core nucleocapsid protein is one of the most conserved proteins and a desirable target for HCV vaccines, especially the protein-based vaccines. In cur...