The study by Kappler et al. (1981) addresses the complex problem of antigen recognition by T cells, particularly focusing on the interaction between antigen and H-2 (Major Histocompatibility Complex, MHC) molecules. The authors developed a method to produce antigen-specific, H-2-restricted T cell hybridomas by fusing normal antigen-specific T cell blasts with a T cell hybridoma (FS6-14.13.AG2) that could be induced to produce interleukin-2 (IL-2) in response to concanavalin A. Four cloned hybridoma cell lines were generated, each capable of producing IL-2 in response to specific antigen and splenic antigen-presenting cells of the appropriate H-2 haplotype. The H-2-restricting elements mapped to the I region, and one hybridoma (AO-40.10) showed an unexpected allo-H-2 response. Additionally, the authors produced hybrids with two antigen/H-2 specificities, but no hybrid displayed a new specificity combining the antigen specificity of one parent with the H-2 specificity of the other. These results support models of dual recognition where the recognition of antigen and H-2 are dependent on each other, rather than independent models. The study provides valuable tools for further investigation into the nature of T cell receptors and their interactions with H-2 products.The study by Kappler et al. (1981) addresses the complex problem of antigen recognition by T cells, particularly focusing on the interaction between antigen and H-2 (Major Histocompatibility Complex, MHC) molecules. The authors developed a method to produce antigen-specific, H-2-restricted T cell hybridomas by fusing normal antigen-specific T cell blasts with a T cell hybridoma (FS6-14.13.AG2) that could be induced to produce interleukin-2 (IL-2) in response to concanavalin A. Four cloned hybridoma cell lines were generated, each capable of producing IL-2 in response to specific antigen and splenic antigen-presenting cells of the appropriate H-2 haplotype. The H-2-restricting elements mapped to the I region, and one hybridoma (AO-40.10) showed an unexpected allo-H-2 response. Additionally, the authors produced hybrids with two antigen/H-2 specificities, but no hybrid displayed a new specificity combining the antigen specificity of one parent with the H-2 specificity of the other. These results support models of dual recognition where the recognition of antigen and H-2 are dependent on each other, rather than independent models. The study provides valuable tools for further investigation into the nature of T cell receptors and their interactions with H-2 products.