Faculty Bibliography

We describe T560, a tissue culture-adapted B lymphoma derived from the gut-associated lymphoid tissue (GALT) of a (B10 x B10.H-2a H-4b)F1 hybrid mouse. This lymphoma is interesting and useful not only because it bears an unusual IgA receptor, fully described elsewhere, but also because it is potentially capable of presenting antigen to T cells restricted by the MHC of either parent. Here we document that T560 cells are IgG2a kappa +, Ia+, B220+, J11d.2+, CD3-, CD4-, CD5-, Mac 1-, Mac 2-, non-specific esterase-. They bind bromelain-treated mouse RBC (BrMRBC) in a PC chloride-inhibitable manner but do not bind SRBC, ox RBC (ORBC) or TNP-ORBC. Two lines, T560.1 and T560.2, and several clones are available. T560.1 and its clones contain low numbers of IgA rosette-forming cells (RFC), intermediate numbers of IgG2a RFC and moderately high numbers of IgG2b RFC; T560.2 and its clones contain moderately high numbers of IgA RFC and low numbers of both IgG2a and IgG2b RFC. Both lines stimulate both B10 and B10.A cells in mixed lymphocyte reactions (MLR) and present keyhole limpet hemocyanin (KLH) to KLH-reactive T cells. T560.2 populations are, however, more efficient possibly because they have somewhat higher proportions of brightly fluorescent Ia+ cells and secrete larger quantities of lymphokine than T560.1 cells. They present PC-conjugated KLH (PC-KLH) approximately 20 times more efficiently than unconjugated KLH, suggesting that their PC binding receptors function in antigen uptake. They constitutively produce IL-1, IL-4 and IL-6, but not IL-2, IL-5 or TGF beta. Neither their IgA nor their IgG receptor expression is affected by IL-4 or by IFNs-alpha, -beta, or -gamma. In their ability to bind BrMRBC and secrete IL-4, they resemble the CH12 lymphoma but differ from it in that they are of F1 hybrid origin, are CD5-, bear IgG2a rather than IgM, do not bind sheep erythrocytes and have a receptor for IgA not present on CH12

A GALT-derived B lymphoma, T560, that bears IgAR is described. T560 is IgG2a kappa +, Ia+, B220+, J11d+, Thy-1-, CD3-, CD4-, CD5-, Mac 1-, Mac 2-, nonspecific esterase negative and binds bromelain-treated mouse RBC but not SRBC or ORBC. It presents antigen, secretes IL-1, IL-4 and IL-6 but not IL-2, IL-5 or TGF beta and appears to be related to the Lyt 1+(CD5) lineage of B cells though it lacks Lyt 1. T560 bears IgAR that, on the cell surface, are completely cross-inhibited by low concentrations of IgM and by high concentrations of IgG2a and IgG2b. They do not appear to represent a cell-surface form of galactosyl transferase. They are inducible by high concentrations of IgA, sensitive to trypsin and insensitive to neuraminidase. They are down-regulated by activation of PKC with PMA, but their recovery is not inhibited by cycloheximide, indicating that they are not degraded or shed. They may either lose their affinity for IgA or be internalized without degradation. Seventy percent of IgA receptor activity is lost when T560 is treated with PI-PLC; part of this loss of activity is due to activation of PKC and is inhibited by staurosporine, but approximately 30% of it is not protected by staurosporine indicating that some, or all, of the IgA receptor of T560 is connected to the cell membrane via a GPI linker. The T560 IgA receptor could be related to the poly-Ig or M cell receptor.(ABSTRACT TRUNCATED AT 250 WORDS)

Four T cell clones, isolated from Peyer's patches of keyhole limpet hemocyanin (KLH)-primed BALB/c mice, were selected on the basis of their ability to help IgA responses by TNP-KLH-primed BALB/c mouse B cells. Two were KLH-dependent both in terms of their own proliferative response and in terms of their help for that of B cells. The other two were autoreactive and helped B cells proliferate independently of the presence of Ag. Both primed and unprimed B cells proliferated to some extent when helped by the KLH-reactive clones in the presence of high concentrations of either KLH or TNP-KLH. Much higher proliferation was, however, induced when primed, but not unprimed, B cells were exposed to the T cells in the presence of low concentrations of TNP-KLH but not KLH, i.e., under conditions favoring direct, cognate interaction between the T and B cells. Only modest IgM, and no IgG or IgA plaque-forming cell (PFC) responses were generated by TNP-primed B cells upon interaction with either autoreactive T cells in the absence of Ag or KLH-reactive T cells in the presence of high concentrations of KLH. For high IgM responses as well as for the appearance of IgG and IgA PFC responses, TNP-KLH was required whatever the source of the T cell help. The isotype ratios depended on the TNP-KLH concentration; IgA responses were highest and IgM responses lowest at the lowest TNP-KLH concentrations suggesting that the precursors of the IgA PFC have higher average affinity for TNP than the precursors of IgM PFC. Overall, the results are compatible with the idea that the precursors of IgA and IgG PFC and many of the precursors of IgM PFC in the long term primed B cell populations used in these experiments require engagement of their Ag-receptors before they express sufficient class II Ag and/or receptors for 'switch' and differentiation factors for cognate interaction with T cells leading to PFC responses

Four BALB/c T cell clones from among a set propagated in the presence of concanavalin A (Con A) were selected on the basis of their ability to produce supernatant factors promoting high IgA plaque-forming cell (PFC) responses by 2,4,6-trinitrophenyl-conjugated keyhole limpet hemocyanin (TNP-KLH)-primed splenic B cells in the presence of TNP-SRBC. Such clones could be derived from cultures containing T cells not only from gut-associated lymphoid tissue, but also from the spleen. The selected clones all proliferated well in the presence of syngeneic, irradiated APC without either Con A or exogenous IL-2, but required both APC and Con A to produce helper factors. Factors from three of the clones helped B cells both to proliferate and to differentiate into IgM, IgG and IgA PFC. Factors from the fourth clone helped B cells differentiate into IgA and IgG PFC and may have promoted switching to these isotypes but did not support either B cell proliferation or generation of IgM PFC. Cross-linking of B cell receptors for antigen was not required for the response to the helper factors since TNP-SRBC were unnecessary and high concentrations of them were actually inhibitory

BALB/cJ X C57BL/10Sn F1 (hereafter called B10F1) hybrids resist challenge with the BALB/c plasmacytoma, MPC-11, by a radiation-sensitive, silica-insensitive mechanism, whereas BALB/cJ X BALB.B F1 (hereafter called BALB.BF1) hybrids are as susceptible to MPC-11 as are homozygous BALB/c mice themselves. To investigate the mechanism of resistance, we have compared anti-MPC-11 immune responses by these F1 hybrids both before and at various times after tumor challenge. Resistance is not determined by natural killer cell reactivity inasmuch as neither hybrid harbors splenic natural killer cells with lytic activity directed against MPC-11. Nor is it determined by antibody-dependent cell-mediated cytotoxicity since neither hybrid produces an appropriate anti-MPC-11 antibody. Spleen cells and lymph node cells from both hybrids are capable of generating high levels of anti-MPC-11 cytotoxic T-lymphocyte activity in both primary and secondary mixed-lymphocyte tumor cell cultures. Such cytotoxic T-lymphocytes protect susceptible hybrids from tumor growth in Winn assays. The susceptible but not the resistant hybrids lose the ability to generate high levels of cytotoxic T-lymphocytes activity in spleen mixed lymphocyte tumor cell cultures by 28 days, and in lymph node mixed-lymphocyte tumor cell cultures by 14 days postchallenge. The reduction in spleen cell reactivity is due to suppression mainly by adherent cells and can be abrogated by pretreatment of the susceptible hybrids with a low dose of Cytoxan 2 days before challenge. This pretreatment does not, however, protect the mice. They develop tumor at the same rate and die at the same time as do controls. Both the late appearance of suppression and the lack of effect on survival of its ablation suggest it to be a concomitant of tumor growth rather than its cause. Resistance to tumor growth in this model system may reflect an enhanced ability of the resistant hybrid to deliver effector cells to the site of tumor implantation

A new antigen, detectable on murine erythrocytes by hemagglutination assay with a (BALB/cCrl X SWR/J)F1 anti-B10.D2n/Sn alloantiserum, is described. Among the inbred and congenic mouse strains tested for reactivity with the antiserum, only the immunizing strain, B10.D2, and its congenic resistant partner, C57BL/10 (B10), reacted. Three other C57 strains, C57BL/6J, C57BL/6By, and C57L, were negative for the antigen. F1 hybrids between B10 and BALB/c, an antigen-negative strain, were positive for the antigen indicating that its expression is dominant. Typing of 39 (BALB/c X (BALB/c X B10)F1) and 62 [BALB/c X B10)F1 X BALB/c) backcross mice revealed that a single gene controls expression of the antigen. The gene is autosomal and not linked to H-2, Ly-4, or the c (albino) or b coat color genes

Patterns of genetic control of hybrid resistance to the BALB/c plasmacytoma LPC-1 were studied for comparison with those to MPC-11, a plasmacytoma investigated previously. The overall patterns of hybrid resistance to the two tumors were similar, i.e., hybrids between BALB/c and BALB congenic resistant (CR) strains, A and A CR strains, SJL and DBA/2 were as susceptible to LPC-1 as BALB/c mice themselves, whereas hybrids between BALB/c and AKR, C57BL/Ks, DBA/1, C57BL/6 (B6), C57BL/10 (B10) and B10 CR strains were resistant to LPC-1 as previously shown with MPC-11. Heterozygosity within the H-2 complex alone was insufficient for resistance to either tumor. Among hybrids between BALB/c and the B10 CR strains, however, the presence of certain H-2 haplotypes influenced the degree of resistance seen and this H-2 effect was different for the two tumors. A sex effect on resistance to LPC-1, but not to MPC-11, was seen among F1 hybrids between BALB/c and DBA/1 although not in any other F1 hybrids. Among ((B10 X BALB/c)F1 X BALB/c) and (BALB/c X (B10 X BALB/c)F1) and ((BALB/c X B10)F1 X BALB/c) and ((BALB/c X B10)F1 X BALB/c) backcross mice, however, significantly more males than females were resistant to LPC-1 and the results of this study are compatible with the idea that in F1 hybrids between BALB/c and B10, resistance to LPC-1 is controlled by two dominant autosomal genes, one of which is sex-limited and neither of which is linked to H-2. In contrast, hybrid resistance to MPC-11 in this cross is controlled by a single gene. Cross-protection experiments indicated that the two tumors share at least one tumor-associated transplantation antigen

Differential distribution of IgA-specific primed Lyt 2- T cells (TH) in favor of gut-associated lymphoid tissue (GALT) has been proposed to account for the high proportion of IgA-producing plasma cells at mucosal versus nonmucosal sites. We find, however, that GALT TH primed enterically with sheep red blood cells (SRBC) contain no more help for IgA responses than peripheral lymph node (PN) TH primed subcutaneously. Moreover, GALT TH are only poorly primed by enterically administered soluble protein antigen and therefore provide less help for all isotypes than PN TH primed subcutaneously with the same antigen. On the other hand, supernatants of GALT TH stimulated with concanavalin A (Con A) in vitro do help higher IgA:IgG plaque-forming cell (PFC) ratios in cultures with 2,4, 6-trinitrophenyl-SRBC (TNP-SRBC) than supernatants from PN and spleen, indicating that, when appropriately stimulated, GALT TH are capable of promoting relatively higher IgA responses than TH from other sources. Responses elicited by either SRBC-primed TH or splenic Con A supernatants in the presence of TNP-SRBC contained higher IgA:IgG PFC ratios than those elicited by linked recognition in the presence of haptenated soluble protein carrier