title: Enhancing effects of interleukin 2-treated peripheral blood mononuclear cells on subsequent B cell differentiation.
abstract: Despite an extensive literature dealing with IL2-induced cytolytic activity, noncytotoxicity-related effects of IL2 on peripheral blood mononuclear cells (PBMC) or T cell function have received less attention. We have focused on the effects of irradiated, IL2-activated PBMC (PBMC*rIL2) on anti-CD3- and formalin-fixed heat-killed Staphylococcus aureus-induced polyclonal B cell differentiation in secondary cultures. PBMC*rIL2 act directly on B cells and cross major histocompatibility complex barriers to augment polyclonal B cell differentiation as measured by plaque-forming cell (PFC) generation. These effects are preferentially mediated by T (both CD4+ and CD8+) cells, and physical contact between effector PBMC*rIL2 and target B cells is not absolutely required for enhanced PFC generation. PBMC*rIL2 must be present for the initial 24 hr of the secondary cultures, indicating that some soluble B cell differentiation factor rapidly released by PBMC*rIL2 mediates the PFC-enhancing effect. Of IL2, IL4, IL5, IL6, IL10, IFN-gamma, and TNF-alpha, only IFN-gamma mRNA is appreciably and reproducibly increased in irradiated, IL2-activated T cells (T cells*rIL2). Nevertheless, exogenous rIFN-gamma cannot mimic and anti-IFN antibodies cannot block the PFC-enhancing effects of T cells*rIL2, indicating that some unidentified soluble factor(s) apart from or in addition to IFN-gamma is involved. IL2-induced effects on T cell noncytolytic function may help explain certain observed immune anomalies in IL2-treated patients, and a better understanding of the IL2-induced effects on T cell noncytolytic function may have ramifications for autoimmune diseases such as SLE.
authors.affiliation: Division of Rheumatology and Immunology, University of Southern California School of Medicine, Los Angeles 90033.
authors.forename: W
authors.initials: W
authors.lastname: Stohl
authors.forename: J E
authors.initials: JE
authors.lastname: Elliott
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: Y G
authors.initials: YG
authors.lastname: Lin
authors.forename: D A
authors.initials: DA
authors.lastname: Horwitz
mesh_terms: D000921:Antibody-Producing Cells / Q000166:cytology / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology; D002454:Cell Differentiation; D006801:Humans; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000494:pharmacology; D007376:Interleukin-2 / Q000494:pharmacology*; D007963:Leukocytes, Mononuclear / Q000502:physiology*; D008211:Lymphocyte Cooperation; D008285:Major Histocompatibility Complex; D011994:Recombinant Proteins; D013601:T-Lymphocytes / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
chemical_list: D007376:Interleukin-2; D011994:Recombinant Proteins; D007371:Interferon-gamma