Reactivity of mouse T-cell hybridomas expressing human Vβ gene segments with staphylococcal and streptococcal superantigens

Abstract

A panel of 15 mouse T-cell hybridomas, each expressing a different human Vβ gene segment (hVβ) in an otherwise mouse T-cell receptor (i.e., mouse α chain and CD3 complex), was constructed by transfection of hVβ/mouse Cβ chimeric T-cell receptor (TCR)-β genes into a mouse T-cell hybridoma recipient lacking the endogenous TCR-β chain. Several qualities that are conferred by the hVβ chain of the TCR are retained in the chimeric human- mouse TCR complex: a large panel of hVβ-specific antibodies specifically stained the hVβ expressed by the mouse T-cell hybridomas. Moreover, hVβ- transfected mouse cells could readily produce interleukin 2 when stimulated by superantigens presented by antigen-presenting cells. These characteristics made it possible to refine the reactivity of 17 superantigen preparations with the available transfected Vβs. Each superantigen gave a characteristic pattern of reactivity on the transfectants. Positive reactivities with some of these transfectants, which differ only by the expressed hVβ, demonstrate unambiguously the superantigenic character of a protein or fraction and its potential to react with the corresponding Vβs. Therefore, these hVβ- transfected cells constituted a valuable tool for determining 'specificity fingerprints' of known or putative superantigens. First, commonly used, commercially available superantigens such as staphylococcal enterotoxin B and toxic shock syndrome toxin-1 (TSST-1) showed additional Vβ reactivities, compared with those of their recombinant counterparts. This stresses the importance of using defined preparations of superantigens for the definition of Vβ specificities. Second, the stimulatory pattern of a strain of Streptococcus pyogenes demonstrated that this strain, unlike others, produces a potent Vβ8-specific superantigen that is as yet undefined at the molecular level.