Strong teratocarcinoma transplantation loci, Gt-1 and Gt-2, flank H-2

Delayed type hypersensitivity responses to the Qa-Tla region of the mouse major histocompatibility complex

We have elicited a small but significant delayed-type hypersensitivity response against the Qa-Tla region of H-2 following immunisation of C57BL/6 mice with cells from the congenic strain C57BL/6.Tlaa. Optimal responses were detected 14 days after immunisation with 10-40 X 10(6) cells. The significance of delayed type hypersensitivity to Qa-Tla is discussed in relation to the genetic loci which map to this region.

H-2 class I antigen expression on mouse teratocarcinoma cell lines

Immunity against PCC3 teratocarcinoma cells (129, H-2b) was induced in allogeneic (C3H, H-2k) mice by preimmunization with L cells (C3H, H-2k) expressing cosmid-introduced Kb or Db genes, but not with nontransfected L cells. In addition, the growth of PCC3 cells in sublethally irradiated (C3H X B6-H-2bm1)F1 and (C3H X B6-H-2bm13)F1 mice bearing the Kbm1 and Dbm13 mutations, respectively, was either prevented, stopped, or delayed in comparison with the (C3H X B6)F1 (k X b) mice, which failed to reject the PCC3 cells. The teratocarcinoma line OC15S was exceptional because it reacted specifically with Kb- and Db-specific (but not Ib-specific) alloantisera, and because Kb- and Db-specific antibodies could be absorbed by OC15S cells. The subpopulation of OC15S cells bearing the ECMA-7 antigen characteristic for embryonic carcinoma (EC) cells was isolated by the fluorescence-activated cell sorter and was shown to react specifically with Kb- and Db-specific antisera. These experiments show that teratocarcinoma cells express antigens similar or identical to the K- and D-region products of differentiated cells. The lack of expression of class I antigens is thus neither a condition nor a consequence of the pluripotentiality of the EC cells. The exact nature of the major histocompatibility complex antigens on EC cells has yet to be established using the methods of molecular biology and biochemistry.

Mice coisogenically immunized against H-2 class I antigens on transfected L cells reject transplanted embryonal carcinoma cells

Evidence is presented of the ability of H-2 class I antigens to function as teratocarcinoma transplantation (Gt) antigens. Coisogenic immunization against H-2 class I antigens expressed on transfected L cells is shown to induce resistance to embryonic carcinoma (EC) cell allografts. The Kb, Db, Dd, and, in appropriate recipients, Ld antigens can function as Gt antigens. The protocol presented may be useful for the molecular identification of other genes encoding histocompatibility antigens.

Minor histocompatibility antigens are developmentally regulated on murine embryonal carcinoma cells and their early differentiated derivatives

Differences in the expression of minor histocompatibility (Hm) alloantigens on two mouse embryonal carcinoma (EC) cell lines and the PYS-2 and T.D.M.-1 differentiated derivatives have been demonstrated by their ability to elicit a cytolytic T lymphocyte response. Experiments involving the use of various responder-target strain combinations and recombinant inbred mice strains have shown that: (1) there are major differences in Hm expression on EC cells compared with differentiated derivatives whose Hm expression appears more like that of adult splenocytes; (2) although both EC cell lines show reduced Hm immunogenicity compared with adult splenocytes, major differences in the expression and possible presentation of Hm between the F9 and PCC3 EC cell lines can be detected by in vivo priming and by in vitro cold competition target experiments. These observations are discussed in relation to the differences in allograft rejection patterns observed with PCC3 and F9 and to possible differences in developmental staging of these cell lines.

Rat natural killer cell and cytotoxic T cell lysis of H-2-negative murine embryonal carcinoma cells

H-2-lacking murine embryonal carcinoma (EC) cells have been proposed as universal targets for natural killer (NK) effectors from different species because their killing appeared to be uncomplicated by potential T cell effector mechanisms (Stern, P. L. et al., Int. J. Cancer 1981. 27:679). While some previous studies had shown that murine cytotoxic T cells were unable to lyse EC cells, rat T killers are shown here to be active against these targets and to be distinguishable from NK cells. Percoll density fractionation of rat peripheral blood lymphocytes enriches in parallel for NK-mediated lysis of both EC or YAC target cells. These NK cells unlike T cells, do not mediate lectin-dependent and cell-mediated cytotoxicity (LDCC) of NK-insensitive target cells. This procedure is thought to reveal the total cytolytic potential of stimulated T cell populations, regardless of specificity. In contrast to previous results with mice, we found that allogeneically primed rat cytotoxic T cells can kill murine EC cells in LDCC and, further, that rat cytotoxic T cells, generated by stimulation with mouse spleen cells in vitro, can lyse murine EC cells directly. This demonstration of T cell lysis of EC cells suggests that either there is a novel mechanism of lysis operating without requirement for major histocompatibility complex (MHC) structures, or EC cells express some hitherto unidentified MHC-like structures on their cell surface.

A gene controlling teratocarcinoma graft rejection mapped inside the t0 haplotype

The embryo-derived teratocarcinoma TC1Ph of the genotype (129 t0/T X C3H)t0/+ and embryonal carcinoma (EC) cell line EC1Ph, established from the TC1Ph, were used as grafts for mice differing only at the T-H-2 interval of chromosome 17. Using exceptional recombinants in this chromosome region a two-gene model of genetic control of EC histocompatibility was proposed. The Cech-1 gene situated at the T end of the T-H-2 interval would control expression of the EC histocompatibility gene located near the H-2 complex.

Male-specific transplantation antigen expression by XY teratocarcinomas PCC7 and 7'

Male-specific antigen expression by XY teratocarcinomas PCC7 and 7' is demonstrated first by the rejection of tumors by female but not by male mice following challenge with these cell lines. Male-specific antigen expression is confirmed by an indirect method in which females are immunized against H-Y antigen by male skin grafts. A variant of PCC7 lacking male-specific antigen expression is described. Analysis of the karyotype and of the DNA from this variant indicate that the loss of male-specific antigen expression is a result of the loss of the Y chromosome. The ability to recover variants that have lost expression of male-specific antigen opens the possibility of their selection after mutagenesis.

Activation of a Qa/Tla class I major histocompatibility antigen gene is a general feature of oncogenesis in the mouse

A cDNA clone corresponding to a mRNA present at elevated levels in transformed fibroblasts encodes a Qa/Tla class I major histocompatibility complex (MHC) antigen. High levels of this mRNA are found in all tumour cells tested; the transcript can undergo alternative splicing; and a repetitive sequence within the transcription unit has the characteristics of a transposable element. The immunological implications of MHC gene activation in tumour cells are discussed.

Teratocarcinoma transplantation antigens are encoded in the H-2 region

Evidence is presented for the existence of teratocarcinoma transplantation antigens (Gt) encoded within the H-2 complex and present also on adult tissues. It has not been possible to separate these Gt loci from H-2 by recombination, and Gt factors map to each end of the H-2 complex. Previous reports indicating separation of all Gt loci from H-2 are reinterpreted. One class of such apparent recombinants has been shown to result from the outgrowth of tumor variants in mice of resistant genotype.

The significance of natural killer activity in the resistance of allogeneic hosts to the embryonal carcinoma cell line F9

A number of mouse strains of known F9 resistance phenotype have been tested for their in vitro natural killer activity against both F9 and YAC target cells. The pattern of in vitro natural killer activity observed does not correlate with the pattern of in vivo F9 resistance. The relative efficiencies of in vitro lysis of the F9 and YAC targets by endogenous natural killer effectors from the 129/Sv, SJL/J, C57Bl/6J, and BALB/cJ strains do, however, parallel each other, even though overall levels of F9 target lysis are very low. Since cold competition experiments indicate that the embryonal carcinoma cell lines tested, F9, PCC4/Aza, and PCC3/A/1, can compete efficiently with YAC as target, this low lysis of embryonal carcinoma cells may be due to an intrinsic lysis resistance. The finding that the parietal endoderm cell line PYS-2 and the trophoectodermal cell line TDM1 also compete with YAC targets in cold competition experiments is discussed in relation to previous reports suggesting that such differentiated derivatives lack natural killer target structures.

Modulation of the immune response to teratocarcinoma in mice sensitized by sperm antigens

Mouse primitive teratocarcinoma cells share a common surface antigen with morulae, preimplantation embryo cells and murine and human spermatozoa. 129/Sv mice were immunized with either spermatozoa and subsequently inoculated with various doses of teratocarcinoma 6050. A significant inhibition or acceleration of tumor growth was observed when compared with controls immunized with compatible fibroblasts. These effects were sex-dependent, both the incidence and tumor growth being suppressed in sperm-immunized males. The opposite effects were observed in sperm-presensitized females. Immune sera obtained from both male and female 129/Sv mice exhibited a high binding activity to human spermatozoa when tested in a cellular radioimmunoassay. Thus, immunization with sperm antigens provides immunotherapeutic and/or enhancing effects in male and female 129/Sv mice, respectively.

Genetics of teratocarcinoma transplantation. III. Genetic control of resistance to F9 tumor formation in allogeneic hosts

Major F9 allograft resistance of strains C57Bl/6J, CBA/J, C3H/He and AKR/J has been shown to be controlled by a small number of recessive genes. These loci are not linked to H-2. Recombinational analysis suggests that the loci responsible for resistance in these strains are at least partially non-overlapping. These results obtained with the blocked F9 embryonal carcinoma cell line are discussed in relation to those reported for embryonal carcinoma strain PCC3/A/l and OTT6050 embryoid bodies, where recessive resistance is H-2 linked.

Teratocarcinoma transplantation rejection loci: genetic localization of the Gt-1 locus on chromosome 17 and the expression of alternate alleles

A series of congenic mice on the BALB/c genetic background have been employed to localize a teratocarcinoma transplantation rejection locus, Gt-1, to the K side of the H-2 locus on chromosome 17. Previous studies have placed the Gt-1sv allele about 8 centimorgans away from the H-2b or H-2bv1 locus. Teratocarcinomas derived from 129/sv mice, Gt-1sv (H-2Kbv1/H-2Dbv1), are rejected by BALB/c(H-2Kd/H-2Dd) and BALB.G mice (H-2Kd/H2D-b, but form tumors in BALB.B (H-2Kb/H2Db) and BALB/5R5 mice (H-2Kb/H2Dd). In the reciprocal tumor-rejection test, a BALB/c teratocarcinoma was rejected by immunized BALB.B mice, but formed tumors in the immunized isogenic BALB/c mouse. These studies demonstrate the reciprocal expression of two Gt-1 alleles, one Gt-1c, in BALB/c mice, and the other, Gt-1sv, in the congenic BALB.B mice, Shedlovsky and co-workers have placed the GT-1 locus in a similar location on the K side of the H-2 locus on chromosome 17.