Immunosuppressive effect of paracoccidioidomycosis sera on the proliferative response of normal mononuclear cells. Identification of a Paracoccidioides brasiliensis 34-kDa polypeptide in circulating immune complexes.

In this paper we relate that sera from paracoccidioidomycosis patients inhibited the mitogen-induced proliferative responses of normal mononuclear cells. Treatment of these sera with 2.5% polyethyleneglycol (PEG), a method classically used to precipitate immune complexes, significantly reduced their inhibitory activity. Immunoblot analysis of the PEG precipitates identified a 34-kDa polypeptide, recognized by rabbit anti-P. brasiliensis IgG. Patient mononuclear cells showed partial restoration of their proliferative capacity after 24 h culture in medium alone, which suggests release of membrane-bound molecules in the culture medium. These findings indicate that circulating P. brasiliensis antigens, complexed or not with antibodies, may play a negative immunoregulatory effect in the mitogen-induced proliferative responses of paracoccidioidomycosis patients.

Polyclonal B cell activation in paracoccidioidomycosis. Polyclonal activation in paracoccidioidomycosis.

Paracoccidioidomycosis (PCM) is often associated with hypergammaglobulinemia and increased serum levels of circulating immune complexes (CIC). In order to investigate whether polyclonal B lymphocyte activation (PBA) is a current process in PCM, we measured the numbers of IgG secreting cells (IgG SC) in the peripheral blood of 16 patients and of 8 healthy controls. The numbers of IgG SC were found to be significantly elevated in PCM patients. We also observed increased serum levels of IgG, IgA and CIC. These data reflect an activation of B lymphocytes in PCM patients.

The possible role of circulating immune complexes in the deficiency of cell-mediated immunity in paracoccidioidomycosis.

1. The nature and extent of immune abnormalities was studied in 28 untreated patients with a chronic moderate form of paracoccidioidomycosis (PCM). 2. The patients presented hyporeactivity to skin tests, diminished lymphocyte transformation by mitogens such as phytohemagglutinin-P and concanavalin A and by Paracoccidioides brasiliensis protein antigen. They also presented peripheral blood leukocytosis but normal absolute numbers of T-cell and T-cell subsets. 3. The patients had increased serum levels of C3d, as well as high levels of circulating immune complexes (CIC) detected by C1q-binding and protein A-binding assays. 4. There was a significant negative correlation between lymphocyte transformation by mitogens and CIC levels which suggested that CIC may be involved in the genesis of the depressed cell-mediated immunity in PCM patients.

Production of a monoclonal anti-hamster thymocyte antibody with mitogenic properties.

A monoclonal antibody (MAb), designated H3, with specificity for hamster lymphocytes, was produced by somatic cell hybridization of myeloma Sp 2/0 and spleen cells of Balb/c mice immunized with suspensions of viable hamster thymocytes. The H3 MAb (IgG 3) reacted specifically with hamster thymocyte surface membranes (immunofluorescent assay). The antibody recognized a protein of an approximate molecular weight of 44,000 Daltons in immunoblots of hamster thymocyte extracts. The soluble H3 MAb presented potent mitogenic properties as indicated by the DNA synthesis induced in in vitro hamster lymphocyte cultures.

Isolation and antigenic characterization of human immunodeficiency virus (HIV) in Brazil.

A retrovirus infecting a Brazilian AIDS patient was isolated and characterized in terms of its reactivity with sera from individuals infected with human immunodeficiency viruses 1 and 2 (HIV-1 and HIV-2). The Western blot analysis revealed that the Brazilian isolate is very similar to the well characterized HIV-1 strain. The serum of the patient from whom the virus was isolated did not react with the 140 kDa envelope glycoprotein specific for HIV-2.