CYTOTOXIC CD4(-LYMPHOCYTES, GENERATED BY MUTANT P21-RAS (12VAL) PEPTIDE VACCINATION OF A PATIENT, RECOGNIZE 12VAL-DEPENDENT NESTED EPITOPESPRESENT WITHIN THE VACCINE PEPTIDE AND KILL AUTOLOGOUS TUMOR-CELLS CARRYING THIS MUTATION() AND CD8(+) T)
Mk. Gjertsen et al., CYTOTOXIC CD4(-LYMPHOCYTES, GENERATED BY MUTANT P21-RAS (12VAL) PEPTIDE VACCINATION OF A PATIENT, RECOGNIZE 12VAL-DEPENDENT NESTED EPITOPESPRESENT WITHIN THE VACCINE PEPTIDE AND KILL AUTOLOGOUS TUMOR-CELLS CARRYING THIS MUTATION() AND CD8(+) T), International journal of cancer, 72(5), 1997, pp. 784-790
Mutant p21-ras proteins contain sequences that distinguish them from n
ormal ras, and represent unique epitopes for T-cell recognition of ant
igen-bearing tumour cells, Here, we examined the capacity of CD4(+) an
d CD8(+) T cells, generated simultaneously by mutant-ras-peptide vacci
nation of a pancreatic-adenocarcinoma patient, to recognize and lyse a
utologous tumour cells harbouring corresponding activated K-ras epitop
es, The patient was vaccinated with a purified 17mer ras peptide (KLVV
VGAVGVGKSALTI), containing the Gly12 --> Val substitution. Responding
T cells were cloned following peptide stimulation, and CD4(+) and CD8(
+) peptide-specific cytotoxic T lymphocytes(CTL) were obtained. Transi
ent pancreatic-adenocarcinoma cell lines(CPE) were established in cell
culture from malignant ascites of the patient, and were shown to harb
our the same K-ras mutation as found in the primary tumour, These cell
s were efficiently killed by the T-cell clones and CD8(+)-mediated cyt
otoxicity was HLA-class-1-restricted, as demonstrated by inhibition of
lysis by anti-class-1 monoclonal antibodies, By employing as targets
different class-1-matched tumour cell lines expressing a 12Val mutatio
n, we were able to demonstrate HLA-B35 as the restriction molecule, an
d further use of peptide-sensitized EBV-B cells as target cells identi
fied VVVGAVGVG as the nonamer peptide responsible for CD8(+)-T-cell re
cognition. These data demonstrate that peptide vaccination with a sing
le mutant p21-ras derived peptide induces CD4(+) and CD8(+) CTL specif
ic for nested epitopes, including the Gly --> Val substitution at codo
n 12, and that both these T-cell sub-sets specifically recognize tumou
r cells harbouring the corresponding K-ras mutation. (C) 1997 Wiley-Li
ss, Inc.