Augmentation of auto-anti-idiotypic antibody production by hapten-reactive helper T lymphocytes

Augmented auto-anti-idiotypic antibody production was effectively achieved by immunization of mice with haptenated myeloma protein in the presence of hapten-reactive helper T lymphocytes. Hapten-reactive helper T-lymphocyte activities were raised in BALB/c mice by immunization with para-azobenzoate (PAB)-derived mouse gamma globulin (MGG) prepared by amidination reaction (PAB_im-MGG). Helper T cell activity was effectively enhanced by pretreatment of mice with a PAB-derived nonimmunogenic copolymer of D-glutamic acid and D-lysine (D-GL) (PAB-D-GL) 3 days before priming with PAB_im-MGG; PAB-D-GL is a potent tolerogen of both PAB-specific suppressor T lymphocytes and PAB-specific B cells. After induction of these enhanced PAB-reactive helper T lymphocytes, mice were immunized with PAB-coupled TEPC-15 myeloma protein (PAB_im-T-15), which was also prepared by amidination reaction. Mice immunized in this way manifested strikingly enhanced titers of auto-anti-idiotypic antibodies, specific for the T-15 idiotype, as compared to control mice which had not been preimmunized with PAB_im-MGG. The ability of PAB_im-MGG preimmunization to facilitate auto-anti-idiotypic antibody production was due to the activity of PAB-reactive helper T cells since PAB-specific B cells had been abolished by prior treatment with PAB-D-GL. The implications of this model for future studies on immunological engineering the analysis of idiotype network phenomena are discussed.     

Idiotype-specific T lymphocytes. I. Regulation of antibody production by idiotype-specific H-2-restricted T lymphocytes

Cytotoxic T lymphocytes (CTL) specific for MOPC-104E myeloma cells of BALB/c origin could be induced in BALB/c, (BALB/c X BALB.B)F1, and (BALB/c X BALB.K)F1 mice. (BALB/c X BALB.B)F1 CTL activity specific for MOPC-104E was effectively inhibited by anti-H-2d but not by anti-H-2b alloantiserum. However, the activity was hardly blocked by specific anti-idiotypic antibodies to MOPC-104E. For further analysis of the recognition of idiotype on target cells by CTL, the effect of those lymphocytes on anti-dextran B1355S antibody-producing B lymphocytes, which have a cross-reactive idiotype to MOPC-104E, was investigated. Lymphocytes from the CTL population did inhibit antibody production by dextran-immune spleen cells, but those from the CTL population specific for irrelevant myeloma cells (MOPC-167) did not. The (BALB/c X BALB.K)F1 CTL population suppressed the antibody production of BALB/c but not of BALB.K. This indicates that F1 cells can preferentially see H-2 antigens of immunizing myeloma cells on target B lymphocytes. The inhibition of antibody production was antigen specific and was only restricted to the PFC that were inhibitable by anti-idiotypic antibodies. The surface phenotypes of the cells that inhibited the antibody production were Thy-1+, Lyt-1-, Lyt-2+, and I-J-. These results strongly suggest that CTL specific for MOPC-104E recognize self H-2 antigens simultaneously with idiotypic determinants on B lymphocytes. Possible immunoregulatory roles of idiotype-specific CTL on antibody production systems are also suggested.     

Immunohistochemical demonstration of surface antigen of human lymphocytes with monoclonal antibody in acetone-fixed paraffin-embedded sections

Although the majority of reported studies have used fresh-frozen sections in detecting surface antigen of lymphocytes in tissue via monoclonal antibody, detailed histological figures can not be obtained by this method. Nor can the antigenicity be preserved for any length of time. A new method for detecting the surface antigen of lymphocytes using fixed and embedded material is presented. Human spleens were fixed in cold acetone, embedded in low melting point paraffin wax, and the thin sections treated with hyaluronidase. Anti-T lymphocyte monoclonal antibody (anti-Leu-1, anti-Leu-2, anti-Leu-3) and anti-HLA-DR were applied on these sections, and the antigen was detected by the ABC (avidin-biotin-peroxidase complex) method. The results were then compared with those of fresh-frozen sections. There was no great difference in detecting T and B cells or their subsets, but the histological figures were substantially better preserved in sections prepared by the present method. Furthermore, the antigenicity was retained in the materials fixed and embedded for more than two years.     

8,9-Epoxyeicosatrienoic acid inhibits antibody production of B lymphocytes in mice

Epoxyeicosatrienoic acids (EETs), synthesized from arachidonic acid by cytochrome P450 epoxygenases, are converted to dihydroxyeicosatrienoic acids by soluble epoxide hydrolase. EETs exert anti-inflammatory effects. However, the effect of EETs on humoral immunity is poorly understood. The present study is to investigate the potential role of EETs on B cell function and mechanisms. We examined the role of EETs on antibody production of splenic B cells from C57BL/6 and apolipoprotein E-deficient (ApoE-/-) mice by means of ELISA. Of the 4 EET regioisomers, 8,9-EET decreased basal and activation-induced B cell antibody secretion. As well, 8,9-EET significantly inhibited B-cell proliferation and survival, plasma cell differentiation and class-switch recombination. Western blot analysis revealed that lipopolysaccharide-induced nuclear translocation of NF-κB could be attenuated by 8,9-EET. Furthermore, germinal center formation was impaired by 8,9-EET in mice in vivo. 8,9-EET may inhibit B-cell function in vitro and in vivo, which suggests a new therapeutic strategy for diseases with excess B cell activation.     

Studies on cytokinin production by Rhizobium

Cytokinin was released into the medium by cultures of both Rhizobium japonicum and R. leguminosarum. Calculations show that the amount of cytokinin released during the logarithmic phase of growth by R. japonicum would be sufficient to initiate the cortical cell divisions necessary to form a root nodule. The substance released by R. japonicum was identified as a zeatin-like compound on the basis of paper chromatography in four solvent systems. Two solvents clearly separated the rhizobial product from N⁶-Δ²-isopentenyladenine and its ribonucleoside. The predominant intracellular cytokinin found in both enzymatic hydrolysates of sRNA and alkaline hydrolysates of total RNA also was similar to zeatin.     

Activation of human B lymphocytes. IX. Modulation of antibody production by products of activated macrophages.

Human monocytes, after in vitro activation by mixed lymphocyte culture (MLC) supernatants produce a monokine (MK) that enhances the plaque-forming cell (PFC) response of pokeweed mitogen (PWM)-stimulated human B lymphocytes. Technical conditions and kinetics of MK production were established. Irradiation of monocytes (5000 rads) does not abolish MK production but heat-killed cells are unable to release the factor. Highly T cell-depleted monocyte populations still produced the PFC-enhancing factor. The same MK has an inconsistent enhancing effect on the PFC responses of lipopolysaccharide (LPS) and nocardia water-soluble mitogen (NWSM)-stimulated B cells. Other macrophage activators such as LPS, phytohemagglutinin (PHA), and latex particles failed to induce consistently the liberation of the PFC-enhancing MK. The target cell for the MK activity on PWM-stimulated B cells appears to be the B lymphocyte itself. These studies demonstrate that soluble monocyte products can have substantial modulatory effects on human B cell function.     

Different patterns of inositol polyphosphate production are seen in B lymphocytes after cross-linking of sIg by anti-Ig antibody or by a multivalent anti-Ig antibody dextran conjugate

Anti-delta antibody conjugated to 2 x 10(6) m.w. dextran (dex) stimulates B lymphocyte proliferation at 10,000-fold lower concentrations than that required by the unconjugated antibody. Dex conjugated antibody also stimulates a greater and more sustained increase in intracellular ionized calcium [( Ca2+]i) than does the unconjugated anti-Ig antibody. Inasmuch as inositol phosphate metabolites have been linked to rises in [Ca2+]i, we analyzed by FPLC the relative amounts of the inositol polyphosphates (IP) in these cells. Anti-Ig-dextran induced a threefold greater increase in total IP than did the unconjugated anti-Ig. Furthermore, in cells stimulated by unconjugated anti-Ig there was a transient induction of I(1,4,5)P3 followed by a rapid accumulation of the I(1,3,4)P3 isomer with little accumulation of I(1,4)P2, whereas in anti-Ig-dex-stimulated cells there was prolonged elevation of I(1,4,5)P3 with more accumulation of I(1,4)P2. In addition, levels of I(1,3,4,5)P4 were maintained over a longer period of time in B cells stimulated by anti-Ig-dex than in those stimulated by unconjugated anti-Ig. The enhanced ratio of I(1,4,5)P3/I(1,3,4)P3 was also seen when suboptimal concentrations of anti-Ig-dex were used which stimulated a level of total inositol phosphate that was similar to that stimulated by the unconjugated anti-Ig. The possibility that the greater stimulation of increased [Ca2+] by anti-Ig-dex than by unconjugated anti-Ig was a predominant factor in influencing the metabolic pathway of I(1,4,5)P3 was excluded. These results show that 1) stimulation of increases in the various IP isomers occurs in anti-Ig stimulated normal B cells as has been shown in B cell lines and 2) that signal transduction and consequent PIP2 hydrolysis that is stimulated by Ag-mediated cross-linking of sIg is strongly influenced by the extent and type of cross-linking that is induced.     

Activated human B lymphocytes express cyclooxygenase-2 and cyclooxygenase inhibitors attenuate antibody production

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for the treatment of inflammatory diseases and target cyclooxygenases 1 and 2 (Cox-1, Cox-2) that are responsible for PG production. Newer Cox-2-selective drugs have been heavily prescribed to quench inflammation. Little is known about whether or not these drugs influence human B lymphocytes and their ability to produce Ab. We report herein that activated human B cells not only highly express Cox-2 and produce PGs, but that the NSAID indomethacin and Cox-2-selective drugs profoundly inhibit the ability of human B cells to produce IgG and IgM in vitro. Human blood B cells highly express Cox-2 mRNA and protein and produce PGs after activation with CD40L, pansorbin, or CD40L plus BCR engagement. Cox-2 is also highly expressed by human tonsil B cells, as shown by immunohistochemistry. Cox-inhibiting drugs modestly affect purified B cell proliferation but profoundly reduce Ab production. The ability of whole blood to produce IgM and IgG following stimulation is also strongly inhibited. In support that Cox-2 plays a seminal role in B lymphocyte Ab production, Cox-2 knockout mice have 64% less IgM and 35% less IgG than normal littermate controls. These findings support that NSAIDs and the new Cox-2-selective drugs have an unsuspected target, the B cell, and attenuate Ab production in humans. Use of NSAIDs may therefore influence autoantibody production in autoimmune diseases and may dampen humoral immunity in response to antigenic challenge/vaccination.     

Specific demonstration of myoepithelial cells by anti-alpha smooth muscle actin antibody

The myoepithelial cells of the sweat, mammary, tracheobronchial, and salivary glands are specifically identified by monoclonal antibody alpha-SM-1, which recognizes alpha smooth muscle actin and not the other actin isoforms. Basal or "reserve" cells in the stratified epithelia and excretory ducts of the salivary glands are negative, as well as all other epithelial cells in various organs. The reaction can be performed in routinely fixed and embedded tissues and is of practical interest in diagnostic histopathology. In immunoelectron cytochemistry, alpha-SM-1 antibody binds to the microfilament bundles in myoepithelial cells of the breast, but does not stain luminal cells and occasional basally located epithelial cells. These basal cells are morphologically and immunocytochemically distinct from the myoepithelial cells, and their nature and significance remain to be clarified.     

Lymphokine production by human melanoma tumor-infiltrating lymphocytes

Summary Lymphokine production by human melanoma tumor-infiltrating lymphocytes (TIL) was studied. Uncultured TIL produced interferon (IFN), but not interleukin-2 (IL-2) or IL-4, in response to anti-CD3 mAb or IL-2. In bulk cultures, IL-2-activated TIL displaying autologous tumor-specific cytotoxicity (CTL-TIL) produced IFN in culture with medium alone, whereas IL-2-activated noncytotoxic TIL did not. Addition of anti-CD3 mAb or autologous tumor cells up-regulated IFN production in IL-2-activated TIL from 10 of 12 or 6 of 12 cases respectively. Those from 4 of 12 cases (2 CTL-TIL and 2 noncytotoxic TIL) produced IL-2 in culture with medium alone. At the clonal level, 5 (4 CD4⁺ and 1 CD8⁺) of 7 autologous tumor-specific CTL clones derived from TIL and 3 (2 CD4⁺ and 1 CD8⁺) of 7 noncytotoxic TIL clones produced IFN in culture with medium alone, which was up-regulated by adding anti-CD3 mAb. Two IFN-producing CTL clones tested produced IL-2 in 4 ×-concentrated supernatants from a 3.5-h culture with medium alone. Furthermore, 2 IFN-producing CTL clones tested expressed mRNA for both IFN and IL-2. IL-2 production and its mRNA expression were up- or down-regulated, respectively, by adding anti-CD3 mAb or autologous tumor cells. IL-4 production was not observed in culture either with medium alone or with IL-2 in any of the cells described above. Anti-CD3 mAb was required for IL-4 production in 3 of 12 IL-2-activated TIL, 2 of 6 CTL clones, and none of 5 noncytotoxic TIL clones. In summary, IFN production was characteristic of melanoma TIL. Some autologous tumor-specific CTL in TIL are suggested to be productive of IL-2 and IFN under unstimulated conditions, both being required for self-activation in an autocrine loop.This work was supported in part by grant CA-47891 from the National Cancer Institute