Comparison of antigen specificity, class II major histocompatibility complex restriction, and in vivo behavior of myelin basic protein-specific T cell lines and clones derived from (BALB/c x SJL/J) mice

Immunization with myelin basic protein (BP) causes experimental allergic encephalomyelitis (EAE) in certain strains of mice. SJL/J (H-2s) is the prototype sensitive strain. Although BALB/c (H-2d) is resistant to EAE through use of an identical immunization protocol, (BALB/c x SJL/J)F1 hybrid mice develop EAE after immunization with BP. T cell clones specific for BP have been isolated from a highly encephalitogenic line of (BALB/c x SJL/J)F1 hybrid T cells raised against bovine BP. The clones were examined for their H-2 restriction and specificity for heterologous forms of BP (mouse, rat, and bovine BP). The results revealed the clones cross-reacting with mouse (self) BP were almost always restricted to F1 hybrid class II major histocompatibility complex (MHC) elements. In contrast, mouse cross-reactive clones derived from a nonencephalitogenic (BALB/c x SJL/J) T cell line raised against rat BP were largely restricted to H-2d elements. These clones did not cross-react with bovine BP. Four additional lines were generated by carrying the original rat and bovine F1 T cell lines on parental antigen-presenting cells thus generating lines biased toward homozygous (SJL/J, H-2s, or BALB/c, H-2d) restriction elements. These "parentally restricted" T cell lines did not induce EAE when injected in vivo. These results suggest that in this F1 strain sensitivity to T cell-induced EAE is associated with epitopes on murine BP that associate with F1 class II MHC restricting elements. In contrast, nonencephalitogenic T cell lines contain a high proportion of murine cross-reactive clones restricted to H-2d, the haplotype of the classically resistant BALB/c mouse. This work illustrates the use of T cell lines and clones in a model system to further analyze the role of MHC restriction elements in autoimmune disease occurring in heterozygous individuals.

Comparison of antigen specificity, class II major histocompatibility complex restriction, and in vivo behavior of myelin basic protein-specific T cell lines and clones derived from (BALB/c x SJL/J) mice

Immunization with myelin basic protein (BP) causes experimental allergic encephalomyelitis (EAE) in certain strains of mice. SJL/J (H-2s) is the prototype sensitive strain. Although BALB/c (H-2d) is resistant to EAE through use of an identical immunization protocol, (BALB/c x SJL/J)F1 hybrid mice develop EAE after immunization with BP. T cell clones specific for BP have been isolated from a highly encephalitogenic line of (BALB/c x SJL/J)F1 hybrid T cells raised against bovine BP. The clones were examined for their H-2 restriction and specificity for heterologous forms of BP (mouse, rat, and bovine BP). The results revealed the clones cross-reacting with mouse (self) BP were almost always restricted to F1 hybrid class II major histocompatibility complex (MHC) elements. In contrast, mouse cross-reactive clones derived from a nonencephalitogenic (BALB/c x SJL/J) T cell line raised against rat BP were largely restricted to H-2d elements. These clones did not cross-react with bovine BP. Four additional lines were generated by carrying the original rat and bovine F1 T cell lines on parental antigen-presenting cells thus generating lines biased toward homozygous (SJL/J, H-2s, or BALB/c, H-2d) restriction elements. These "parentally restricted" T cell lines did not induce EAE when injected in vivo. These results suggest that in this F1 strain sensitivity to T cell-induced EAE is associated with epitopes on murine BP that associate with F1 class II MHC restricting elements. In contrast, nonencephalitogenic T cell lines contain a high proportion of murine cross-reactive clones restricted to H-2d, the haplotype of the classically resistant BALB/c mouse. This work illustrates the use of T cell lines and clones in a model system to further analyze the role of MHC restriction elements in autoimmune disease occurring in heterozygous individuals.

Correlations between carbon-13 nuclear magnetic resonance and X-ray crystallography for pyrroles containing electron-withdrawing groups

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Progenitor cells in the thymus: most thymus-homing progenitor cells in the adult mouse thymus bear Pgp-1 glycoprotein but not interleukin-2 receptor on their cell surface

Pgp-1-positive and interleukin-2-receptor (IL-2R)-positive cells are both minor (less than 5%) subpopulations within the adult thymus. A thymocyte population enriched for these two cell types, obtained by killing the bulk of thymocytes with anti-Thy-1 antibody and complement, contains thymus-homing progenitor cells which can transiently repopulate the thymus of irradiated recipients. Using two-color immunofluorescence, we demonstrate that the Pgp-1+ and IL-2R+ cells present in this enriched population represent largely nonoverlapping subsets, although some cells do express both markers. We also show by depletion of these two cell types that the bulk of the thymus-homing progenitors present in this enriched population are found in the Pgp-1+ population, and not in the IL-2R+ population. We discuss the relationship between the thymus-homing progenitors in this depleted thymus subpopulation and the thymus-homing progenitors present in the thymus as a whole.