Modulatory effects on immunoglobulin synthesis and secretion by lymphocytes from immunodeficient patients

Incubation of peripheral lymphocytes (PBL) from normal donors with pokeweek mitogen (PWM) induced terminal differentiation by B lymphocytes to immunoglobulin (Ig) synthesizing and secreting plasma cells. B cells from hypogammaglobulinemic patients with different primary immunodeficiencies failed to undergo functional differentiation after similar treatment with PWM. Co-cultures of BL from normal donors and hypogammaglobulinemic patients often resulted in deviations, both positive and negative, from expected levels of PWM-stimulated intracellular Ig biosynthesis. Suppression of B-cell differentiation was manifested by PBL from patients with several different primary immunodeficiencies, including infantile sex-linked agammaglobulinemia. Immunoregulatory activities were noted to vary with the normal donor used in co-culture experiments and with time. Cell populations that were active in influencing B-cell differentiation to functional plasma cells did not have an appreciable modulatory effect on T-lymphocyte responses to mitogens. These observations may provide a functional subclassifications for immunoregulatory cells in man.

Suppression of immunoglobulin synthesis and secretion by peripheral blood lymphocytes from normal donors

Concanavalin A (Con A)-treated peripheral blood lymphocytes from healthy volunteer donors have been shown to suppress proliferative responses associated with thymus-derived lymphocytes (T-cells). The present investigations demonstrate that peripheral blood lymphocytes incubated with Con A for 48 hr can abrogate pokeweed mitogen-stimulated differentiation of bone-marrow-derived (B) lymphocytes to immunoglobulin-synthesizing and -secreting plasma cells. This effect was manifested when washed Con A-treated peripheral blood lymphocytes were added to pokeweed mitogen-stimulated cocultures containing fresh autologous or allogeneic mononuclear cells, and it did not appear to involve cytotoxicity. Parallel control cultures consisting of mononuclear leukocytes incubated for 48 hr in the absence of Con A also had immunoglobulin suppressor activity in mixing experiments. This effect, however, was most pronounced when preincubated cells were added to fresh autologous pokeweed mitogen-stimulated peripheral blood lymphocytes. Cell mixtures containing peripheral blood lymphocytes demonstrated a spectrum of immunoregulatory effects ranging from suppression to enhancement of pokeweed mitogen-stimulated immunoglobulin synthesis and secretion. Several functional subclasses of suppressor cells that reflect varying levels of specific activity have thus been demonstrated in human beings. Moreover, a degree of genetic identity appears to be required for the expression of "weak" immunoregulatory influences.

Antigenic changes of DBA/2J mastocytoma cells when grown in the BALB/c mouse

A 10-day growth period of the DBA/2J strain-specific P815-X2 mastocytoma in the BALB/c mouse altered the antigenicity of the tumor cell surface. The in vivo-modified mastocytoma cells differed from mastocytoma cells grown in the original DBA/2J mice in suspectibility to lysis by immune peritoneal exudate cells, in vitro antigenic recognition by cytotoxic T-cells, and immunizing capacity in allogeneic C57BL/6 mice. Propagation of the altered tumor cells in the original host or maintenance in tissue culture for 40 hours restored complete susceptibility to lymphocyte-mediated cytotoxicity.

Levamisole augments the cytotoxic T-cell response depending on the dose of drugs and antigen administered

The effects of levamisole on the immune of cytotoxic thymus-derived lymphocytes were studied. An optimum relative dose of antigen and and lavamisole appears to be crucial for levamisole to augment development of cytotoxic cells.

Serological precipitation method for studying biosynthesis and secretion of immunoglobulins by human peripheral blood lymphocytes

A reproducible, serological method to quantify radiolabeled immunoglobulin (Ig) synthesized and secreted by human peripheral blood lymphocytes is described. In contrast to indirect precipitation (rabbit antihuman Ig and goat antirabbit Ig), the direct coprecipitation method using human IgG and rabbit antihuman IgG F (ab)2 showed much smaller, non-specifically precipitable radioactivity (i.e., 2 approximately 14%) without affecting Ig radioactivity.

Subpopulations of chicken B lymphocytes

Immunoglobulin-synthesizing cells from the spleen and bursa were fractionated by the 1 X G sedimentation velocity technique and characterized by their ability to synthesize immunoglobulin and by staining with fluorescent anti-light chain chain. Four subpopulations of immunoglobulin-synthesizing cells were identified. In the bursa, slowly sedimenting (S 2.3 mm/hr) and rapidly sedimenting (S greater than 3.5 mm/hr) subpopulations with surface immunoglobulin were present; in the spleen, a slowly sedimenting (S 2.3 mm/hr) subpopulation with surface immunoglobulin and plasma cells (S greater than 3.5 mm/hr) with large concentrations of intracellular immunoglobulin existed. The subpopulations differed most markedly in their ability to synthesize immunoglobulin (cpm Ig synthesized/10(6) Ig-positive cells); the rates of immunoglobulin synthesis were in the ratio 1:2:1:900. The slowly sedimenting B cells from the spleen and both subpopulations of B cells from the bursa released small amounts of immunoglobulin into the culture media, whereas, the plasma cells released immunoglobulin at a rate as much as 3700 times greater. Bursal B cells could be further distinguished from splenic B cells by a greater amount of DNA synthesis.

Isoantiserum-augmented development of lymphocyte-mediated cytotoxicity

Passive administration of anti-P-814 isoantiserum (IS) with P-815 mastocytoma was shown to augment the development of T-lymphocyte-mediated cytotoxicity (LMC). The LMC activity augmented by IS was specific to immunizing tumor cells, but required the simultaneous administration of P-815 tumor cells and anti-P-815 serum, suggesting that the antigen-antibody complex is involved in the development of specific cytotoxic T cells. The serum component responsible for augmented development of LMC activity appeared to be IgM in that the augmenting activity fractionated in the void volume of a G-200 Sephadex column and appears very early after immunization. Our experimental results suggest the development of specific T-cell cytotoxicity can be directly regulated by specific IgM antibodies.

Biosynthesis of membrane bound Ig and secretion of Ig by chicken lymphoid cells

The metabolic turnover of membrane proteins of chicken lymphoid cells is studied, using a double isotope labeling technique (i.e., [14C]amino acid pulse and [3H]leucine chase). Compared with other membrane proteins, the metabolic turnover of membrane bound immunoglobulins (M-Ig) is very slow. There was no difference in the turnover between M-Ig and specific antigen binding receptor immunoglobulins. Immunoglobulins appear to be a stable constituent of the lumphocyte membrane. Cellular kinetic experiments show that the rate of biosynthesis of secreted immunoglobulins (S-Ig) is nearly ten times as much as that of M-Ig, suggesting that metabolic pathway leading to M-Ig are distinct from those leading to S-Ig. The difference in 3H/14C ratios between S-Ig and M-Ig reflects the rate of biosynthesis of these immunoglobulins by two types of bursa derived lymphoid cells.

A novel fluorimetric determination of sphingosine

A fluorimetric method to determine sphingosine and the related bases at nmole level is described. For the fluorescence labeling of the long chain bases, pyridoxal was conjugated to the amino groups of the compounds. The method is applicable to sphingolipids after hydrolysis or methanolysis even in the presence of largeamount of contaminating amino-containing substances.

Concancvalin A binding proteins of lymphoid cell surface

A Concanavalin A binding protein of chicken lymphoid cells was isolated by affinity chromatography of intact lymphoid cells. This protein with a mol wt of 160,000 daltons revealed two peptides (30,000 and 20,000 daltons) in SDS-acrylamide gel electrophoresis.

Heterologous specific antiserum for identification of human T lymphocytes

Peripheral blood lymphocytes (PBL) from two patients with Bruton-type agammaglobulinaemia were used for the preparation of heterologous anti-human T cell-sera which were absorbed with cultured B lymphoblast cells, peripheral blood lymphocytes from a patient with chronic lymphatic leukaemia and `adherent' cells. Using multiple criteria, one antiserum (ATCS) was shown to be specific for T lymphocytes. This antiserum asserts the existence of human-specific T-lymphocyte antigen(s) (HTLA) and provides another method for identifying human T cells. In the presence of rabbit complement, ATCS was cytotoxic for 65·5% (range 49–78) of normal PBL and 97% of thymocytes (the latter cells having also a higher surface density of HTLA than PBL). The study of PBL from a variety of patients showed that the percentage of ATCS-sensitive cells was high in Bruton-type agammaglobulinaemia, variable from patient to patient and from time to time in common variable hypogammaglobulinaemia and generally low in active lepromatous leprosy, in patients under antilymphocyte globulin therapy and in chronic lymphatic leukaemia. Cultured lymphoblasts from various B cell lines or from a Burkitt lymphoma cell line were resistant to ATCS.

Thymus-dependent lymphocytes of peripheral blood in leprosy patients

Study of the numbers of thymus-derived lymphocytes by the rosette assay (T-RFC) in patients with leprosy reveals that lower than normal numbers of T-RFC are regularly seen in those patients with the active lepromatous form of this disease. Essentially normal numbers of T-RFC were found in inactive lepromatous, borderline, and indeterminate types of leprosy. The lowest percentages and lowest absolute numbers of T-RFC were encountered in patients with lepromatous leprosy resistant to chemotherapy. Patients with lepromatous leprosy complicated by erythema nodosum leprosum show numbers of T-RFC that are more nearly normal than the numbers of T-RFC in patients with uncomplicated lepromatous leprosy. These findings are discussed with respect to the pathogenesis of lepromatous leprosy and the T-RFC deficiency demonstrated in this disease. The possibility that transient defects in T-RFC numbers or function may predispose to lepromatous leprosy is proposed.

Escape from isoantiserum inhibition of lymphocyte-mediated cytotoxicity

Isoantiserum (IS) inhibition of lymphocyte-mediated cytotoxicity (LMC) was studied using an in vitro (51)Cr release assay system. In the early phase of incubation, LMC was competitively inhibited by IS. However, as the incubation continued, LMC irreversibly overcame IS inhibition (the "escape" phenomenon). Addition of fresh antiserum did not alter the course of the escape. Low-temperature incubation of isoantibody-coated target cells delayed the onset of the escape. We have excluded the possibility that the escape phenomenon is induced by complement or by LMC mediated by antigen-antibody complex. It is hypothesized that antibody directed toward an actively metabolizing target cell induces an alteration in the cell membrane that alters further interaction with the antibody. However, sensitivity to lymphocyte cytotoxicity is maintained.