that the observations with anti-aP-antibody are 
analogous to the reactions between thymocytes 
and natural antigens, which must also engage the 
cell via ap, not CD3. 
Several conclusions were drawn from these ex- 
periments. First, the studies showed that the imma- 
ture pool of a(3^ thymocytes, formerly thought to 
be a single pool of cells, consisted of two different 
populations, only one of which could be deleted by 
receptor ligation. It is therefore tempting to predict 
that the forces of positive selection might act on 
the nondeletable pool. Second, these data support 
the hypothesis that increases in intracellular Ca^^ 
are part or all of the signal for thymocyte death. 
PUBLICATIONS 
Third, different stages of thymocyte development 
seem to be defined by different degrees of coupling 
between a^-receptor proteins and the proteins 
with which they are associated, those of CD3, 
which are thought to transduce a^-initiated signals 
to the cell bearing them. 
Dr. Marrack is also Member of the Department of 
Medicine at the National Jewish Center for Immu- 
nology and Respiratory Medicine and Professor in 
the Departments of Biochemistry, Biophysics, and 
Genetics, and of Microbiology, Immunology, and 
Medicine at the University of Colorado Health Sci- 
ences Center. 
Books and Chapters of Books 
Marrack, P., and Kappler, J. 1989. Antigen recognition and tolerance. Consequences for the T cell repertoire. 
In Current Communications in Molecular Biology. Perspectives on the Molecular Biology and Immunol- 
ogy of the Pancreatic B Cell (Hanahan, D., McDevitt, H.O., and Cahill, G.F., Jr., Eds.). Cold Spring Harbor, 
NY: Cold Spring Harbor, p 169. 
Articles 
Blackman, M.A., Marrack, P, and Kappler, J. 1989. Influence of the major histocompatibility complex on posi- 
tive thymic selection of VplTa"*" T cells. Science 244:214-217. 
Carbone, A.M., Marrack, R, and Kappler, J.W 1988. Demethylated CD8 gene in CD4"'" T cells suggests that 
CD4"'" cells develop from CD8"'" precursors. Science 242:1174-1176. 
Carbone, A.M., Marrack, P, and Kappler, J.W 1988. Remethylation at sites 5' of the murine Lyt-2 gene in asso- 
ciation with shutdown of Lyt-2 expression. J Immunol 141:1369-1375. 
Fenton, R.G., Marrack, P., Kappler, J.W, Kanagawa, O., and Seidman, J.G. 1988. Isotypic exclusion of 78 T cell 
receptors in transgenic mice bearing a rearranged P-chain gene. Science 241:1089-1092. 
Finkel, T.H., Marrack, P , Kappler, J.W , Kubo, R.T., and Cambier, J.C. 1989. apT cell receptor and CD3 trans- 
duce different signals in immature T cells. Implications for selection and tolerance. J Immunol 142:3006- 
3012. 
Kappler, J. , Kotzin, B., Herron, L., Gelfand, E.W, Bigler, R.D., Boylston, A., Carrel, S., Posnett, D.N., Choi, Y , 
and Marrack, P 1989. Vp-specific stimulation of human T cells by staphylococcal toxins. Science 244:811- 
813. 
Kappler, J.W, Kushnir, E., and Marrack, P 1989. Analysis of Vpi7a expression in new mouse strains bearing 
the Vpa haplotype. J Exp Med 169:15^5-1541. 
Kotzin, B., Kappler, J.W, Marrack, PC, and Herron, L.R. 1989. T cell tolerance to self antigens in New Zea- 
land hybrid mice with lupus-like disease. J Immunol 143:89-94. 
Kubo, R.T., Born, W, Kappler, J.W, Marrack, P, and Pigeon, M. 1989- Characterization of a monoclonal anti- 
body which detects all murine ap T cell receptors. J Immunol 142:2736-2742. 
Marrack, P, and Kappler, J.W 1988. The T-cell repertoire for antigen and MHC. Immunol Today 9:308. 
Marrack, R, McCormack, J., and Kappler, J. 1989. Presentation of antigen, foreign histocompatibility complex 
proteins and self by thymus cortical epithelium. Nature 338:503-505. 
McDuffie, M., Roehm, N., Kappler, J.W , and Marrack, P 1988. Involvement of major histocompatibility com- 
plex products in tolerance induction in the thymus. J Immunol 141:1840-1847. 
Continued 
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