An activated murine B cell lymphoma line (A-20) produces a factor-like activity which is functionally related to human natural killer cell stimulatory factor.
In the present article we show that supernatants derived from lipopolysaccharide (LPS) or phorbol 12-myristate 13-acetate (PMA)-stimulated A-20 B cell lymphoma are able to induce polyclonal immunoglobulin (Ig) secretion by normal B cells in a T-cell-dependent manner. This activity could be blocked by neutralizing monoclonal antibodies against interferon-gamma, but not by monoclonal antibodies against interleukin (IL)-2, IL-4, IL-5, IL-6, IL-10 and granulocyte macrophage colony-stimulating factor (GM-CSF) or even a polyclonal antibody against tumor necrosis factor (TNF)-alpha. Furthermore, A-20 supernatants induced the production of measurable amounts of interferon-gamma by normal murine spleen cells and activates natural killer (NK) cells. Fractionation of factor-rich supernatants on a Sephacryl S-200 column revealed that the factor activity is located in the fractions corresponding to a molecular mass of 160-150 kDa and 80-70 kDa. The biological activities found in the A-20 supernatant are very similar to the ones described for the recently cloned human IL-12/NK cell stimulatory factor. These results suggest the existence of a murine analogous factor for the human IL-12 produced by A-20 B cell lymphoma.
Department of Immunology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil.
J
J
Mengel
L
L
Daré
G M
GM
Daré
M
M
Delgado
A
A
Nomizo
J S
JS
Silva
A
A
Campos-Neto
D000818:Animals; D007136:Immunoglobulins / Q000096:biosynthesis; D007371:Interferon-gamma / Q000096:biosynthesis*; D018664:Interleukin-12; D007378:Interleukins / Q000502:physiology*; D007694:Killer Cells, Natural / Q000276:immunology*; D008070:Lipopolysaccharides; D008213:Lymphocyte Activation; D016393:Lymphoma, B-Cell / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008970:Molecular Weight; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D007136:Immunoglobulins; D007378:Interleukins; D008070:Lipopolysaccharides; D018664:Interleukin-12; D007371:Interferon-gamma; D013755:Tetradecanoylphorbol Acetate