Major histocompatibility complex-specific recognition of Mls-1 is mediated by multiple elements of the T cell receptor.

Abstract

SummaryWe have recently shown that recognition of the mouse mammary tumor virus 9-associated superantigen (vSAG-9) by routine VB17 ~ T cells is strongly influenced by the major histocompatibility complex (MHC) class II haplotype of the presenting cells, resulting in a form of MHC-restricted recognition. This finding was unexpected, because T cell recognition of another well-characterized retroviral superantigen, minor lymphocyte-stimulating antigen 1 (Mls-1), had been shown to be independent of the MHC haplotype of the presenting cell. To determine whether recognition of vSAG-9 and Mls-1 is fundamentally different, we undertook an extensive analysis of MHC haplotype influences on vSAG-9 and Mls-1 recognition by panels of T cell hybridomas. Our results show that, although most hybridomas recognized Mls-1 regardless of the MHC haplotype of the presenting cells, as previously described by others, some hybridomas exhibited unique patterns of MHC fine specificity. Thus, T cell recognition of vSAG-9 and Mls-1 is not fundamentally different, but the apparent differences can be explained in terms of frequency. The MHC fine specificity of individual Mls-l-reactive hybridomas was influenced by both VB and non-V~/T cell receptor (TCR) elements. First, the influence of the VB element was apparent from the observation that VB8.2 + hybridomas were significantly more MHC specific in their recognition of Mls-1 than V~8.1 hybridomas. Second, a role for the TCR ol chain was implicated from the distinct patterns of fine specificity of Mls-1 reactivity among a panel of transgenic hybridomas that expressed an identical B chain (V/~8.1DB2JB2.3CB2). Sequence analysis revealed that junctional residues of the TCR oe chain and/or Vo~/Jo~ combinations influenced the MHC haplotype fine specificity for Mls-1. Third, D/3J~ influences were implicated, in that the transgenic hybridomas expressed distinctive patterns of Mls-1 fine specificity not represented among V~8.1 + nontransgenic hybridomas. The findings that T cell recognition of endogenous superantigen is MHC specific, and that this specificity correlates with non-V~ elements of the TCR, support the hypothesis that there is a direct interaction between the TCR and either polymorphic residues of the MHC class II molecule or haplotype-specific dominant peptides presented by class II.B acterial and retroviral superantigens are characterized by their ability to stimulate T ceils based predominantly on the expression of specific TCR VB dements (1, 2), although non-V/3 dements of the receptor have recently been shown to have an influence on reactivity (3-6). MHC class II molecules are necessary for presentation of superantigens to T cells, but these responses are not classically MHC restricted, in that individual T cells are able to recognize a single superantigen presented in the context of multiple class II molecules. However, it has been shown that class II isotypes and alleles vary in their effectiveness as presenting molecules. For example, studies with murine clones and hybridomas speci...

META-Controlled env-Initiated Transcripts Encoding Superantigens of Murine Mtv29 and Mtv7 and Their Possible Role in B Cell Lymphomagenesis

“…possible that MHC class II molecules on the lymphoma cells influence their relative abilities to preferentially present one or another vSAg (33,34). It is of great interest that vSAg7 expressed in SW ϫ J-1 lymphomas appears to stimulate V␤16 ϩ T cells.…”

MMTV Superantigens Coerce an Unconventional Topology between the TCR and MHC Class II

“…Given the lack of an MMTV SAG crystal structure, it is challenging to predict how vSAGs force MHCII/TCR association. Previous analyses of the response of mature peripheral T cells against vSAGs have clearly established that non-Vb components of the TCR are involved in the pMHCII/vSAG7 complex recognition (78)(79)(80)(81). The Va-chain was shown to be an important part of the complex, and a skewed repertoire in responding cells has been identified (82,83).…”

Identification of MHC Class II-Associated Peptides That Promote the Presentation of Toxic Shock Syndrome Toxin-1 to T Cells

“…1 and 2) (16,20). Briefly, 3 ϫ 10 5 T2-I-A b or T1-I-A b cells or 1 ϫ 10 5 I-A b L cells were seeded into 96-well plates in complete culture medium (21).…”

“…Where indicated, synthetic peptides were added and incubated for 2-4 h at 37°C. Next, titered amounts of TSST-1 or SEB were added to the cultures (in a volume of 25 l) followed by 1 ϫ 10 5 SAg-reactive hybridoma cells in 75 l. The cultures were incubated for an additional 24 h at 37°C, and the culture supernatants were harvested to assess IL-2 secretion in a standard bioassay (16,20). One unit of recombinant human IL-2 (R&D Systems, Minneapolis, MN) is equivalent to 160 U in our assay.…”

“…T cell fusions were performed as described previously (16). Briefly, spleen cells were harvested from C57BL/6 mice and stimulated with 50 g/ml of either SEA or TSST-1 for 72 h in vitro.…”