Strong stimulation of DNA synthesis (up to 150-fold) and blast transformation can be induced in mouse spleen cells by Fc fragments of human IgG. The mitogenic response is optimal on day 5 of culture and is dependent on the concentration of Fc fragments with a sedimentation rate of 3-5S. Intact IgG is also stimulatory, but only when modified by heat aggregation, and produces only a 10-fold incre...

Hematoporphyrin [1,3,5,8-tetramethyl-2,4-bis(hydroxyethyl)-porphin-6,7-dipropio nic acid dihydrochloride derivative] (HPD) is a compound that was studied in a number of laboratories because of its cytocidal activity after activation by light. Modification of immune function seen during the photochemotherapeutic studies prompted attempts to determine the effect of HPD on the immune and hemopoiet...

Human T-cell growth factor (TCGF), a mitogenic protein that appears in the media of cultured lymphocytes after phytohemagglutinin-stimulation, has been purified more than 400-fold from serum-free conditioned media by using a sequence of ion exchange chromatography and gel filtration. The purified growth factor elutes as a broad peak from DEAE-Sepharose, focuses diffusely at a pH of about 6.8 on...

The 15,000-molecular-weight polypeptide (p15) of feline leukemia virus (FeLV) was shown to impair normal lymphocyte function in vitro and to abrogate immunity to feline oncornavirus disease in vivo. FeLVp15 suppressed concanavalin A-induced blast transformation of normal feline lymphocytes by 68%, while other virion proteins had no effect. p15 suppression was not due to toxicity, nor was p15 a ...

Relatively pure populations of human T and B lymphocytes were obtained from blood and tonsils using density gradient centrifugation in bovine serum albumin. Antigen alone was incapable of triggering the B lymphocyte into blast transformation or to secrete antibody. However, supernatants from tetanus toxoid-stimulated T cells obtained from immune donors contained a factor mitogenic for B lymphoc...

The Empire Rheumatism Council's controlled trial (1960) showed that gold salts benefit patients with rheumatoid arthritis. However, side-effects still occur with this treatment despite regular blood counts and urine examinations and, although the incidence of severe reactions has probably been reduced by careful attention to the dose and number of injections given, serious haematological compli...

PPD-sensitized monocytes and macrophages from tuberculin-positive subjects are both capable of inducing blastogenic transformation of autologous lymphocytes . Incorporation of thymidine-3H and morphological transformation were always greater in lymphocyte cultures containing macrophages than in those containing monocytes . More lymphocytes entered the first detectable S phase in cultures contai...

Pertussis B mitogen (PBM), isolated from culture supernatant fluids of Bordetella pertussis, is a potent mitogen for mouse and human lymphocytes. In mice, > 95% of the blast cells recovered from PBM cultures bear surface immunoglobulins. Therefore, PBM seems to induce proliferation of mouse B lymphocytes, but not T cells. The proliferative response observed is nonspecific because cells from all...

PPD-sensitized monocytes and macrophages from tuberculin-positive subjects are both capable of inducing blastogenic transformation of autologous lymphocytes. Incorporation of thymidine-(3)H and morphological transformation were always greater in lymphocyte cultures containing macrophages than in those containing monocytes. More lymphocytes entered the first detectable S phase in cultures contai...

The circulating lymphocyte has recently been reported to have many possible functions. Though once believed to be short-lived end cells (1), lymphocytes present in the peripheral blood are now known not only to recirculate for up to 5 days, but also to be capable of "homing" in lymph nodes and in the spleen (2). These cells have been reported to be capable of producing antibody (3), of transfor...