Lymphocyte effector molecules: an vitro production method for obtaining liter volumes of supernatants from mitogen-stimulated human lymphocytes

Mononuclear cell factors that inhibit fibroblast collagen synthesis. I. In vitro conditions determining their production and expression

Peripheral blood mononuclear cells (PBMC) incubated either with phytohaemagglutinin-P (PHA) under serum-free conditions or with tuberculin purified protein derivative in the presence of 5% human blood group AB serum released into the culture medium factors that decreased collagen synthesis by dermal fibroblasts. These factors were first detected after incubation of PBMC with PHA for 24 h and were produced by non-adherent cells. The decrease in collagen synthesis was observed despite changes in conditions of fibroblast culture, the addition of a cross-linking inhibitor, and the use of different fibroblast cell lines.

Amphotericin B modifications of peripheral blood lymphocyte and tonsil lymphocyte responses to concanavalin A

Peripheral blood lymphocytes (PBL) were shown previously to be activated to incorporate 3H-thymidine by concanavalin A (con A). Amphotericin B (Am B) was reported to be both immuno-enhancing and suppressive. We investigated the response of PBL and tonsil lymphocytes (TL) to con A in culture, and the effect of Am B on these responses. PBL were activated by con A as expected, and the magnitude of the response diminished as cell density increased. The responses of PBL usually were significantly enhanced by Am B at 2.5 or 5 micrograms/ml, but 10 micrograms Am B/ml significantly inhibited the con A response. TL had relatively high rates of spontaneous proliferation, but Am B was a potent inhibitor of this. TL responded to con A just as well as PBL, and Am B strongly inhibited these responses too. When TL were cultured with various doses of con A in the presence of 5 or 10 micrograms Am B/ml, the shape of the dose curves resembled those of PBL stimulated in the absence of Am B except that the incorporation of 3H-thymidine increased with increasing cell density. It was concluded that Am B at 2.5-5.0 micrograms/ml enhanced the response of PBL to con A and suppressed the response at 10 micrograms/ml. All doses of Am B inhibited both spontaneous proliferation and con A-induced proliferation in TL. In spite of this inhibition, the TL population responded to various doses of con A in the presence of Am B.

Inhibition and stimulation of leukocyte adherence by soluble factors from murine lymphocytes

Activation of murine spleen cells with either specific antigen or mitogen resulted in the production of soluble factors capable of either inhibiting or stimulating the adherence of normal peritoneal cells. Leukocyte adherence inhibition factor (LAIF) and leukocyte adherence stimulation factor (LASF) were detected using the original leukocyte adherence inhibition (LAI) assay as performed with haemocytometers. An important factor in determining both the production and detection of adherence-modulating factors was the serum content in both the preparation and testing of supernatants favoured LAIF, whereas a lower serum content resulted in LASF predominating. With mitogen (concanavalin A) -activated cells, variable production of adherence inhibitory and stimulatory activities was found, but LASF appeared to be favoured at low concentrations of concanavalin A and serum. Adherence inhibitory and stimulatory factors in concanavalin A-generated spleen cell supernatants were separable on Sephacryl S-200 columns. LAIF had a molecular weight of less than 55,000 daltons, whereas most LASF activity was greater than 70,000 daltons. The occurrence of adherence-modulating factors with opposing effects may be a potential source of variability in LAI assays.

Species specificity of guinea pig and human lymphotoxin colony inhibitory activity

The species specificity of lymphotoxin colony inhibitory activity was measured by in vitro colony growth of neoplastic and nonneoplastic cells in the presence of lymphotoxin from the same or from a xenogeneic species. Growth of guinea pig, rat, and mouse neoplastically transformed cells was inhibited by guinea pig lymphotoxin. Colony formation of benzo(a)pyrene transformed 104C1 guinea pig cells was inhibited 45% with lymphotoxin at 42 units/ml medium; nontransformed 104 and 118 guinea pigs cell were not inhibited. Alpha L929, a spontaneously transformed mouse cell, was completely inhibited. Dimethylbenz(a)anthracene (DMBA) 3T3-D and R4-2 mouse transformed cells were inhibited 40 and 100%, respectively, but parental nontransformed 3T3 cells were not inhibited. DMBA transformed R-2 and R-6 rat cells were inhibited 20 and 40%, respectively, but secondary nontransformed fetal rat cells were unaffected. In contrast, normal human xeroderma pigmentosum, Lesch-Nyhan and 1220 fibroblast cells were inhibited 50-60%. No inhibition of HeLa or RPMI 2650 human tumor cells occurred. HeLa and RPMI 2650 cells, however, were inhibited 30 and 60%, respectively, by human lymphotoxin, but normal human and tumorigenic guinea pig cells were unaffected. Thus, guinea pig and human lymphotoxin exhibit species specific and differential cytotoxicity mechanisms for normal and tumor cells.

Antibodies against human lymphokines: I. Methods for induction of antibodies capable of neutralizing stable (alpha) and unstable (beta) lymphotoxins released in vitro by activated human lymphocytes

Various methods were employed to induce antibodies in rabbits that were capable of neutralizing different families of lymphotoxins (LT). Both stable (alpha-LT) and unstable (beta-LT) molecules, released by activated human lymphocytes in vitro, were neutralized. The different LT families were first separated into their respective groups by physical-chemical methods. Immunization with small quantities of antigen yielded a high percentage of responder animals. Techniques were developed for eliciting alpha-LT antibodies using as little as 2--3 ml of a cell-free supernatant. The situation was more difficult, however, when the unstable beta-LT molecules were employed as antigens. We found that because of the low concentration and lability of beta-LT in supernatants, the immunizing dose had to be: a) handled rapidly, b) larger than that used with the alpha-LT, and c) injected at closer intervals and over a longer immunization protocol. Physical-chemical studies supperted the concept that the LT-neutralizing activity in the immune serum was immunoglobulin.