Synergistic effects of lipopolysaccharide on phytohemagglutinin- and concanavalin A-induced deoxyribonucleic acid synthesis in human peripheral blood lymphocytes: participation of T lymphocytes

Antigen-specific proliferative response of peritoneal exudate lymphocytes primed with antigen and bacterial lipopolysaccharide: the roles of Ia+ accessory cells and IL-2

In vitro antigen-specific proliferation was investigated in a lymphocyte population that had been taken from the peritoneal exudate cells (PEC) of C3H/HeN mice (Iak) primed in vivo with both bacterial lipopolysaccharide (LPS) and horse red blood cells (HRBC) and had been purified by passage through a nylon fiber column (Nfc). The proliferative response of the Nfc-passed lymphocytes primed with HRBC and LPS [T(HRBC+LPS) cells] depended on the dose of antigen in the cultures, and the response was higher than that of cells prepared from mice primed with HRBC alone [T(HRBC) cells]. No response was seen in the cells prepared from the LPS-primed mice [T(LPS) cells] or normal mice [T(N) cells]. The response of the T(HRBC) cells was abolished by previous treatment of the cells with anti-Iak antibody and complement (C), whereas the response of the T(HRBC+LPS) cells was retained after the same treatment, indicating that the Ia- T(HRBC+LPS) cells can proliferate in response to antigen in spite of Ia+ accessory cell-depletion. Supernatants from the cultures of Ia- T(HRBC+LPS) cells in the presence of HRBC showed abundant IL-2 activity, while those of Ia- T(HRBC) cells did not. The IL-2 should be produced by the L3T4 cell population in T(HRBC+LPS) cells in response to antigen, since the previous treatment of the cells with anti-L3T4 antibody and C abrogated the production.(ABSTRACT TRUNCATED AT 250 WORDS)

IgG subclass distribution of serum antibodies against lipopolysaccharide from Bacteroides gingivalis in periodontal health and disease

Serum IgG1, IgG2, IgG3 and IgG4 antibody levels directed against lipopolysaccharide (LPS) from Bacteroides gingivalis were measured in the sera from systemically healthy subjects with and without periodontitis. An enzyme-linked immunosorbent assay was used that included coating of microtiter plates with LPS, and subsequent incubation with patient sera followed by mouse monoclonal subclass-specific antibodies, biotinylated sheep anti-mouse IgG and alkaline phosphatase conjugated to streptavidin. Anti-LPS IgG antibodies were dominated by IgG2, and moderate amounts only of IgG1, IgG3 and IgG4 were found. The periodontitis patients had significantly higher anti-LPS IgG1, IgG2 and IgG3 levels when compared to the subjects with healthy periodontium (p less than 0.05, Mann-Whitney test).

The roles of interleukins in the synergistic effect of B-cell mitogens with concanavalin A on hydrocortisone-resistant thymic cell proliferation

Investigations were made to determine the roles of interleukin (IL)-1 and IL-2 in the synergistic enhancement of DNA synthesis by concanavalin A (Con A) and bacterial lipopolysaccharide (LPS) or butanol-extracted water-soluble adjuvant (Bu-WSA) from Bacterionema matruchotii in cultures of thymic cells taken from hydrocortisone (HC)-treated C3H/HeN (LPS-responsive) and C3H/HeJ (LPS-non-responsive) mice. When the C3H/HeNCrj cells were cultured in the presence of Con A and LPS or Bu-WSA together, [3H]thymidine [( 3H]TdR) uptake of the cells was enhanced synergistically in comparison with those cultured with either one of the mitogens alone. The synergistic effect on thymic cells was dependent on Ia-positive accessory cells, since a previous treatment of the cells with anti-Iak serum and complement inhibited the response, and the inhibition could be relieved by the addition of either purified peritoneal exudate macrophages (Mø) or splenic B lymphocytes. The co-stimulation of cells with Con A and LPS or Bu-WSA also enhanced their production and release of thymic cell growth factor(s) into the culture medium. The amounts of IL-1 and IL-2 in the culture supernatants were sufficiently high to explain the activities of the growth factor(s). On the other hand, enhanced IL-2 production without significant increase in IL-1 was seen in the co-cultures of anti-Ia+ cell deprived thymic cells and purified splenic B cells prepared from C3H/HeNCrj mice in the presence of Con A and LPS or Bu-WSA, and it was seen in the cultures of C3H/HeJ thymic cells with Con A and LPS. These results suggest that the synergistic effect of Con A and LPS or Bu-WSA on the proliferative response of HC-treated thymic cells is mainly due to the enhanced production of IL-2 and its action to increase cell growth, and there are two pathways by which the enhancement of IL-2 production by Con A and LPS or Bu-WSA can occur: an IL-1-dependent pathway, or an IL-1-independent one.

Role of interleukin 2 on enhancement of concanavalin A-induced human peripheral blood lymphocyte proliferation by murine B cell mitogens

Murine B cell mitogens such as bacterial lipopolysaccharide (LPS), butanol-extracted water soluble adjuvant (Bu-WSA), dextran sulfate (DS), synthetic muramyl dipeptide (MDP), and its analog MDP-Lys (L18) do not show any mitogenic ability in vitro on human peripheral blood lymphocytes or mixed cell populations of purified T and B cells obtained from the lymphocytes in an ordinary culture system. However, these mitogens are capable of enhancing the mitogenic effect of concanavalin A (Con A) in the cultures. In the presence of one of these mitogens, the activity of interleukin 2 (IL 2), but not interleukin 1, in the supernatants obtained from cultures containing Con A-stimulated T cell and B cell populations was higher than that of control cultures. The role of the newly produced IL 2 in the synergistic effect of the mitogens in human lymphocyte cell cultures was discussed.

The immunomodulatory action of frentizole, a novel immunosuppressive agent

The in vitro effects of frentizole and methylprednisolone on human PBL were examined. Both drugs exhibited differential effects on lymphocyte subpopulations. Frentizole was more effective in suppressing human lymphocytes responding to Con A and PWM, than it was in cells activated by PHA, specific antigen, or alloantigen. Methylprednisolone, on the other hand, was more inhibitory for cells stimulated by PHA, specific antigen, or alloantigen. These data suggest that frentizole has a preferential effect on the cytotoxic/suppressor subpopulation of human T lymphocytes while methylprednisolone appears to preferentially affect the helper/inducer subset. Differences in potency between the two drugs were also observed. Methylprednisolone was better able to maintain its inhibitory effects during longer periods of culture than frentizole. Both agents were less effective if their addition to the culture was delayed 24-48 hrs and neither drug was very effective in overcoming the adjuvant action of poly A:U on mitogenically activated human PBL.