title: Increased T gamma and T mu cells in BALB/c mice with IgG and IgM plasmacytomas and hybridomas.
abstract: The results of previous studies in our laboratory have shown that mice bearing plasmacytomas and hybridomas that secrete IgA or IgE are accompanied by increased frequencies of Lyt-1-2+ T lymphocytes bearing Fc receptors (FcR) for IgA (T alpha) or IgE (T epsilon), respectively. The present study was undertaken to examine whether IgG- or IgM-secreting tumors influenced the frequency of T lymphocytes that express FcR for IgG or IgM. We studied mice bearing IgG- and IgM-secreting plasmacytomas and hybridomas. BALB/c mice injected subcutaneously with the IgG-secreting hybridoma HDP1 (gamma 1 kappa, anti-TNP) were sequentially examined for the frequencies and Lyt phenotypes of splenic lymphocytes bearing FcR for IgG (T gamma), IgM (T mu), and IgA (T alpha). A threefold increase in the frequency of T gamma lymphocytes that were Lyt-1-2+, L3T4- was seen. The frequencies of T mu and T alpha lymphocytes in these mice were not significantly altered. Similarly, mice injected subcutaneously with the IgM-secreting plasmacytoma MOPC 104E (mu lambda, anti-dextran) or the IgM-secreting hybridoma C1D1 (mu kappa, anti-ox RBC) were examined sequentially for the frequencies of T gamma, T mu, and T alpha lymphocytes. Mice with established IgM subcutaneous tumors showed a twofold increase in splenic, nylon wool-nonadherent T mu lymphocytes. This was associated with a relative increase in Lyt-2+ splenic T lymphocytes and a relative decrease in Lyt-1+ splenic T lymphocytes. No changes were observed in the frequencies of either T gamma or T alpha lymphocytes. These studies extend to IgG and IgM the observation that plasmacytomas and hybridomas secreting immunoglobulins of a specific isotype cause an expansion of T lymphocytes bearing FcR specific for the corresponding isotype. The expansion of FcR+ Lyt-1-2+ T lymphocytes likely represents an exaggerated, but otherwise normal, immunoregulatory response of the host. These cells may be an important element in the regulation of isotype expression.
mesh_terms: D000818:Animals; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly; D000954:Antigens, Surface; D005260:Female; D006825:Hybridomas / Q000276:immunology / Q000378:metabolism*; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000378:metabolism*; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000378:metabolism*; D007958:Leukocyte Count; D051379:Mice; D008807:Mice, Inbred BALB C; D010641:Phenotype; D010954:Plasmacytoma / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D011961:Receptors, Fc; D017452:Receptors, IgG; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000145:classification / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly; D000954:Antigens, Surface; C036832:Fc(alpha) receptor; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011961:Receptors, Fc; D017452:Receptors, IgG; C035311:immunoglobulin M receptor