Cytotoxic activity of lymphocytes. VI. Heterogeneity of cytotoxins in supernatants of mitogen-activated lymphocytes.
Two different lymphotoxins synthesized by human blood lymphocytes stimulated with phytohemagglutin (PHA) are described. The two toxins are called alpha-LT and beta-LT relative to their elution order on gel chromatography. Their m.w. are 75,000 and 45,000 daltons, respectively. Both toxins appear as early as 7 hr after the addition of PHA, with the amount of beta-toxin exceeding that of alpha-LT initially. Both toxins are differentiated from a third toxin (adherent cell toxin, ACT) made by plastic-adherent cells without requiring mitogen-stimulation. Depletion of macrophages or B cells does not affect the synthesis of either lymphotoxin. Monospecific antisera were elicited to alpha-LT. Antisera elicited to beta-LT also neutralized alpha-LT but to a significantly lesser degree. Alpha-LT appears to be the lymphotoxin described by most other workers. Beta-LT is unstable at 37 degrees C which may explain why the low m.w. lymphotoxin has not been described previously.
D000818:Animals; D002448:Cell Adhesion; D002474:Cell-Free System; D006801:Humans; D007106:Immune Sera / Q000302:isolation & purification; D037102:Lectins / Q000494:pharmacology; D008214:Lymphocytes / Q000378:metabolism*; D008233:Lymphotoxin-alpha / Q000032:analysis* / Q000096:biosynthesis / Q000302:isolation & purification; D009500:Neutralization Tests; D014066:Palatine Tonsil / Q000378:metabolism; D011817:Rabbits; D013154:Spleen / Q000378:metabolism
D007106:Immune Sera; D037102:Lectins; D008233:Lymphotoxin-alpha