Identification of a 40S ribosomal protein S4-derived H-Y epitope able to elicit a lymphoblast-specific cytotoxic T lymphocyte response.
OBJECTIVE
The superior graft-versus-leukemia (GVL) effect of the female-to-male stem cell transplantation is partially independent from the concomitant graft-versus-host reactivity. However, the antigenic basis of this selective GVL response remains enigmatic, because no H-Y antigens with hematopoietic-restricted expression were identified. In this study, we report a novel H-Y epitope that is preferentially recognized on activated proliferating lymphocytes.


METHODS
We generated a CTL clone YKIII.8 that showed reactivity toward male B*5201+ CD40-activated B cells, EBV-lymphoblastoid cell lines, and phytohemagglutinin-activated T-cell blasts but little or no reactivity toward fibroblasts, CD14+ cells, or unstimulated B and T cells. The antigen recognized by YKIII.8 was identified by screening of a cDNA expression library, and its pattern of expression was investigated.


RESULTS
cDNA of the male isoform of 40S ribosomal protein S4 was found to encode the antigenic peptide TIRYPDPVI, which was recognized by YKIII.8. Western blot analysis showed that rapidly proliferating cells overexpress the RPS4 protein in comparison with nonrecognized cell subsets. Retroviral transfer of YKIII.8 T-cell receptor resulted in preservation of the lymphoblast-specific reactivity pattern.


CONCLUSIONS
Our findings suggest that CTL specific to certain epitopes of ubiquitously expressed H-Y antigens may specifically target lymphoblasts, contributing to the selective GVL effect of female-to-male stem cell transplantation.
Ivanov
Roman
R
Jordan Laboratory for Hemato-oncology, Department of Hematology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands.
Aarts
Tineke
T
Hol
Samantha
S
Doornenbal
Angeline
A
Hagenbeek
Anton
A
Petersen
Eefke
E
Ebeling
Saskia
S
D015153:Blotting, Western; D019013:CD40 Antigens / Q000276:immunology; D049109:Cell Proliferation; D018076:DNA, Complementary; D000939:Epitopes; D005260:Female; D020544:Graft vs Leukemia Effect / Q000276:immunology*; D006182:H-Y Antigen / Q000276:immunology*; D015235:HLA-B Antigens / Q000276:immunology; D059950:HLA-B52 Antigen; D019337:Hematologic Neoplasms / Q000276:immunology; D006801:Humans; D008297:Male; D020033:Protein Isoforms; D012269:Ribosomal Proteins / Q000737:chemistry* / Q000276:immunology*; D012737:Sex Factors; D033581:Stem Cell Transplantation; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D019013:CD40 Antigens; D018076:DNA, Complementary; D000939:Epitopes; D006182:H-Y Antigen; D015235:HLA-B Antigens; C501279:HLA-B*52:01 antigen; D059950:HLA-B52 Antigen; D020033:Protein Isoforms; D012269:Ribosomal Proteins; C031798:ribosomal protein S4