Regulation of HLA-DR gene by IFN-gamma. Transcriptional and post-transcriptional control

IFN-gamma increases the synthesis and level of mRNA of the HLA class I and II genes, in human cells such as melanomas which normally express both classes of molecules. It also induces the surface expression and mRNA synthesis of HLA-DR genes on cells which normally do not express HLA class II genes such as skin fibroblasts. We have investigated the mechanism by which IFN-gamma increases mRNA levels for class II MHC antigens in human cells. For this purpose, we have studied the effect of IFN-gamma on HLA-DR-alpha transcription rate in two different human cell types: VAL melanoma and JDA2 skin fibroblasts. HLA-DR-alpha mRNA is spontaneously produced in VAL cells and its level is enhanced upon IFN-gamma treatment. We demonstrate here that IFN-gamma increases the transcription of HLA-DR-alpha gene in this cell line. However, the discrepancy observed between HLA-DR-alpha mRNA and transcriptional rates led us to postulate that IFN-gamma also regulates the HLA-DR-alpha gene post-transcriptionally. In the course of these experiments, we found also that human skin fibroblasts, which do not contain detectable amounts of HLA-DR-alpha mRNA, spontaneously transcribe the HLA-DR-alpha gene.

Regulation of HLA-DR gene by IFN-gamma. Transcriptional and post-transcriptional control

IFN-gamma increases the synthesis and level of mRNA of the HLA class I and II genes, in human cells such as melanomas which normally express both classes of molecules. It also induces the surface expression and mRNA synthesis of HLA-DR genes on cells which normally do not express HLA class II genes such as skin fibroblasts. We have investigated the mechanism by which IFN-gamma increases mRNA levels for class II MHC antigens in human cells. For this purpose, we have studied the effect of IFN-gamma on HLA-DR-alpha transcription rate in two different human cell types: VAL melanoma and JDA2 skin fibroblasts. HLA-DR-alpha mRNA is spontaneously produced in VAL cells and its level is enhanced upon IFN-gamma treatment. We demonstrate here that IFN-gamma increases the transcription of HLA-DR-alpha gene in this cell line. However, the discrepancy observed between HLA-DR-alpha mRNA and transcriptional rates led us to postulate that IFN-gamma also regulates the HLA-DR-alpha gene post-transcriptionally. In the course of these experiments, we found also that human skin fibroblasts, which do not contain detectable amounts of HLA-DR-alpha mRNA, spontaneously transcribe the HLA-DR-alpha gene.

The p12f2/TaqI Y-specific polymorphism in three groups of Italians and in a sample of Senegalese

The TaqI/p12f2 Y-specific RFLP was studied in 258 Italians (69 from North, 74 from Centre-South and 115 from Southern Sardinia) and in 65 Senegalese. The two allelic fragments of 10 and 8 kb characterizing this polymorphism were both found in the Italians but only the 10 kb band was found among the Senegalese. The observed frequency of the 8 kb allele was 32.4% in Central-Southern Italians, 17.4% in Northern Italians and 13.0% in Southern Sardinians. The last figure is significantly lower than that (34.3%) previously reported for a smaller sample of the same population.

[An XX male newborn infant. A genetic and endocrinologic study]

The second child of a non consanguineous couple had a male phenotype with two intrascrotal testes of normal size however a scrotum bifidum was noted. The karyotype of the child was 46 XX and the parents one's was normal. No Y specific sequence was detected by using four Y specific probes (47 B, 12 F3, 52 D and 118). During the first semester of life, hormonal investigations showed a normal testicular function.

Testis-specific transcripts detected by a human Y-DNA-derived probe

A genomic sequence (12f3), derived from the long arm of the human Y chromosome, detects a 1·6 kb mRNA, expressed in human and mouse testis, but not in other tissues tested by Northern blot analysis. Using 12f3 as a probe, a mouse cDNA, designated PL5, was isolated from an adult mouse testis cDNA library. The profile obtained by Southern blot analysis using PL5 as probe under high-stringency conditions, reveals that 12f3 probably represents a Y-located pseudogene which was derived from an autosomally located gene. Southern blot analysis of different vertebrate species, using probe PL5, shows that this gene has been highly conserved during evolution. Preliminary in situ hybridizations on testis tissue sections indicate that PL5 is expressed during the postmeiotic stages of male germ cell differentiation and thus may play a role during spermatogenesis. A second cDNA, also obtained from the testis cDNA library, weakly crossreacts with 12f3. This cDNA, designated PL10, detects a mRNA of approximately 4 kb which is highly expressed in mouse testis, but not in male or female mouse liver. The gene corresponding to this cDNA is also well conserved among vertebrates.

Further cytologic evidence for Xp-Yp translocation in XX males using in situ hybridization with Y-derived probe

Chromosome preparations from seven subjects with aberrations of sex chromosomes were utilized for in situ hybridization studies with the tritium-labeled Y-derived probe p50f. Two subjects had a pseudodicentric chromosome consisting of two copies of Yp and a portion of Y long arm; two were XX males [46,XX,t(Xp;Yp)], one was missing part of the Y short arm, and another had t(5p;Yq); in addition cells from an XYY male as well as a normal 46,XY male, and a 46,XX female, were hybridized with the same probe. The hybridization technique of Harper and Saunders (1981) was used. There was excess labeling of the Yp/paracentromeric regions in the cases with the normal Y, the XYY, the pseudodicentric Y, and the 5/Y translocation. No significant label was seen on metaphases from the normal 46,XX female or the female with the partially missing Y short arm. Excess label was present on the X short arm in the cases of the XX males; there were 8% and 9.5% of cells with label. The combined cytogenetic and hybridization data indicate that one X short arm in these XX males has undergone a translocation with Yp, and that genes for sex determination probably reside on the distal half of the Y short arm.

Small deletions of the short arm of the Y chromosome in 46,XY females

Structural anomalies of the sex chromosomes provide a means to study the location of genes responsible for sex determination. Recently, a type of sex reversal in humans, the 46,XX male, was shown to result in some cases from translocation of Y chromosome material to the X chromosome. In the present report, another type of sex reversal, the 46,XY female, is shown to result, in two cases, from small deletions of the short arm of the Y chromosome. Prometaphase chromosome analysis showed a 46,X,Yp- karyotype. Several Y chromosome-specific DNA probes were found to be deleted in the two female patients. DNA analysis showed that the two deletions were different but included a common overlapping region likely to be essential for male determination.

[XX male syndrome: a study model of the genetic determination of the male sex]

Using Y-specific probes, issued from a library of the human Y chromosome, DNA from about 30 XX men has been studied by the Southern technique. Two groups of patients could be distinguished: one with Y genetic material, the second, without Y DNA. Among XX males with Y sequences there was a genetic heterogeneity with a variable amount of Y DNA sequences. These Y DNA sequences come from the short arm of the Y chromosome and are probably translocated to the paternal X. Concerning the other group, in which no Y sequence could be detected, either Y DNA was present but was not detected, or the mechanism of maleness was Y-independent.

Interferon response sequence potentiates activity of an enhancer in the promoter region of a mouse H-2 gene

The expression of class I transplantation antigens encoded in the major histocompatibility complex (H-2 in mouse, HLA in man) can be induced by alpha-, beta- and gamma-interferons. Both transcriptional and post-transcriptional mechanisms have been postulated. Recently, a common sequence has been found in the promoter region of several human genes responsive to IFN-alpha. The promoters of H-2Kb and several other mouse class I genes contain a similar interferon response sequence. We show here, in a transient assay, that the H-2Kb promoter can be induced by all three types of interferon and that the interferon response sequence is necessary for induction to occur. However, the response sequence is active only when associated with a functional enhancer sequence which we have recently identified in the promoter of H-2Kb and other class I genes. The combination of these two sequences can render a heterologous promoter responsive to interferon, irrespective of its orientation relative to the cap site.

Prenatal identification of a Y-chromosome deletion by Y-specific single copy DNA probes

A sex chromosome deletion was identified in the course of prenatal diagnosis for maternal age. Ultrasound pictures revealed male fetal sex and a comparison with the father's Y chromosome suggested that the altered chromosome might be a de novo deletion of the Y chromosome. DNA hybridization with five human Y-specific probes shows that, among the Y-specific sequences recognized by the probes, only two of them are absent. The normal infant, at birth, was mosaic 46, XYq-/46,XY.

Qualitative differences in effects of recombinant alpha-, beta- and gamma-interferons on human peripheral blood leukocytes in vitro

The in vitro effects of bacteria-produced human interferons alpha 2, beta and gamma on several properties of peripheral blood leukocytes from different healthy donors were compared. Treatment with HuIFN-alpha 2 or HuIFN-beta resulted in inhibition of the proliferative response to phytohaemagglutinin and in closely parallel induction of 2'-5'-oligoadenylate synthetase activity. In contrast, HuIFN-gamma had no significant effect on these two activities. However, all three HuIFN were able to enhance natural killer cell cytotoxicity and the expression of HLA-DR surface antigens, with only quantitative variations from donor to donor. Similar results were observed with glycosylated recombinant hamster-cell-derived HuIFN-gamma and with natural HuIFN-gamma. These data demonstrate qualitative differences in the effects of HuIFN-gamma compared to those of HuIFN-alpha 2 or -beta on cells of the immune system.

A human Y-linked DNA polymorphism and its potential for estimating genetic and evolutionary distance

A human DNA sequence (p12f2), derived from a partial Y-chromosome genomic library and showing homology with the X and Y chromosomes and with an undetermined number of autosomes, detected two Y-specific restriction fragment length variants on male DNA that had been digested with Taq I and Eco RI. These variants may have been generated through a deletion-insertion mechanism and their pattern of holoandric transmission indicates that they represent a two-allele Y-linked polymorphism (RFLP). By means of DNA from patients with inborn deletions in chromosome Y, this polymorphic DNA site was mapped to the interval Yq11.1-Yq11.22. The frequency of the rarest allele was about 35 percent in Algerian and Sardinian human males, whereas it was only 4 percent among Northern Europeans. The p12f2 probe also detected Y-specific DNA fragments in the gorilla and chimpanzee. In view of the monosomy of the Y chromosome in mammalian species, Y-linked RFLP's may prove to be more useful than autosomal or X-linked markers in estimating genetic distances within and between species.

[Normal male phenotype or hypospadias and female karyotype. XX male syndrome in children and adolescents]

A morphologically normal 46 XX karyotype has been found in 8 patients with male phenotype, either normal (3 cases) or hypospadiac (5 cases) studied at age 1 month to 15 years. Five had cryptorchidism. Pubertal follow-up was obtained in 6 patients and showed that they had hypogonadism with small testes, and a mean adult height of 163 cm. The hormonal investigations gave normal results before puberty, then after the onset of puberty a hypergonadotropic hypogonadism. Testicular biopsy showed alterations from age 8 years. Studies using Y-specific probes in 3 patients have shown the presence of Y genetic material in 2 and absence in 1, thus demonstrating genetic heterogeneity of the XX males.

A monoclonal antibody against a Burkitt lymphoma associated antigen has an anti-Pk red blood cell specificity

The blood group specificity of a rat IgM monoclonal antibody (38-13) directed against most EBV-positive or -negative Burkitt's lymphoma was investigated. The target antigen was previously identified as the neutral glycolipid ceramide trihexoside (CTH), a substance which accumulates in red cells from very rare individuals of the Pk phenotype and which appears as a normal intermediate in the biosynthetic pathway of the P blood group antigen (globoside). The 38-13 antibody agglutinated Pk1 and Pk2 red cells at 4 degrees C with a very high titre but was inactive against native P1, P2 and p erythrocytes, although a very weak activity was noticed towards papain-treated P1 and P2 erythrocytes. These results were confirmed by an indirect radio-binding assay which also demonstrated that the 38-13 antibody reacted with lymphocytes, fibroblasts and EBV-positive lymphoblastoid cell lines derived from Pk1 and Pk2 individuals but not from other donors. These findings demonstrate that the 38-13 monoclonal antibody previously considered as specific of Burkitt cells could be routinely used as an anti-Pk blood group typing reagent. The mechanism of CTH accumulation in Burkitt cells and Pk red cells is probably different and might be associated respectively with the activation of an alpha-4-galactosyltransferase or the genetic blockage of a beta-3-N-acetylgalactosaminyltransferase.

Agar human T cell colony growth promoted by a B + null cell-derived lymphokine distinct from IL 2

Human T cell agar colonies can be grown under PHA stimulation from either mature T cells or their E rosette-negative (E-), OKT3- peripheral blood and bone marrow precursors. Colonies comprise a majority of mature E+, OKT3+ cells and a minor (5 to 10%) population of immature E-, T3-, T8-, T4-, DR+, T10+, RFB1+ cells, which upon replating in subculture, can generate secondary colonies of OKT3+, E+, OKT4+, OKT8+ cells. Secondary colony formation can serve as a test for growth requirement of colony precursors, because it depends on the presence of both PHA and a colony-promoting activity (CPA) recovered in PHA-stimulated B + null or T + adherent cell supernatants. CPA production by B + null cells was not affected by their treatment with OKT3 or D66 (T11-like) monoclonal antibodies (MAB) + complement but was abolished by an anti-HLA-DR MAB + complement. However, B cells sorted by panning with the same anti-HLA-DR MAB did not release CPA, demonstrating the requirement of both B cells and null cells for CPA production. Neither IL 2 nor IL 1 could account for B + null cell-derived CPA.

Agar human T cell colony growth promoted by a B + null cell-derived lymphokine distinct from IL 2

Human T cell agar colonies can be grown under PHA stimulation from either mature T cells or their E rosette-negative (E-), OKT3- peripheral blood and bone marrow precursors. Colonies comprise a majority of mature E+, OKT3+ cells and a minor (5 to 10%) population of immature E-, T3-, T8-, T4-, DR+, T10+, RFB1+ cells, which upon replating in subculture, can generate secondary colonies of OKT3+, E+, OKT4+, OKT8+ cells. Secondary colony formation can serve as a test for growth requirement of colony precursors, because it depends on the presence of both PHA and a colony-promoting activity (CPA) recovered in PHA-stimulated B + null or T + adherent cell supernatants. CPA production by B + null cells was not affected by their treatment with OKT3 or D66 (T11-like) monoclonal antibodies (MAB) + complement but was abolished by an anti-HLA-DR MAB + complement. However, B cells sorted by panning with the same anti-HLA-DR MAB did not release CPA, demonstrating the requirement of both B cells and null cells for CPA production. Neither IL 2 nor IL 1 could account for B + null cell-derived CPA.

Human cells allosensitized in vitro release soluble suppressor factors: presence of at least two distinct factors

Human cells allosensitized in vitro release suppressor "factors" (SF) capable of inhibiting a primary mixed lymphocyte reaction (MLR). Preincubation experiments with SF of either responders or stimulators in MLR suggested the presence of at least two distinct suppressor activities: one called SFR, acting on certain responders including the SF producer; the other called SFNR, acting on stimulators in all MLR. These activities can be separated using sorbents composed of monoclonal anti-HLA-DR antibodies on the one hand and mouse or rabbit IgG on the other hand. SFR is found in the effluent and SFNR in the eluate of these sorbents. The SFNR-binding properties are shared by a murine suppressor factor called immunoglobulin-binding factor or IBF. Moreover SFNR, like IBF, is capable of suppressing a secondary in vitro IgG response through the species barrier.

Induction of the expression of HLA class I antigens on K562 by interferons and sodium butyrate

Using sodium butyrate and alpha, beta, and gamma interferons as inducing agents it has been possible to demonstrate the triggering of HLA class I antigen synthesis in the K562 cell line. This cell line, widely used to study hemopoietic differentiation, does not naturally express HLA antigens. This effect was confirmed by the detection of HLA class I antigens on the cell membrane with specific monoclonal antibodies, by immuneprecipitation, and by isolation of specific HLA ABC messenger RNA, in the induced cells. No synthesis of HLA class II antigens was observed. Because leukemic cells can be considered as a model representing certain stages of normal hemopoietic differentiation, the expression of HLA antigens on K562 cells induced to differentiate could be interpreted as an event related to the process of differentiation itself. The lack of expression of DR antigens may result from a genetic defect as observed for beta 2-microglobin in Daudi cells.

Evidence of a preferential inactivation of the paternally derived X chromosome in a 46,XX true hermaphrodite

The pattern of inheritance of several X polymorphic markers is studied in the pedigree of a 46,XX true hermaphrodite. The results of the Xga, 12E7, and G6PD segregation analysis favour the hypothesis of a preferential inactivation of the paternally derived X chromosome.

Transformation of LMTK- cells with purified HLA class I gene. VI. Serological characterization of HLA-B7 and AW24 molecules

Serological characterization of HLA-B7 and HLA-AW24 class I molecules following transfection of murine LMTK- cells with purified HLA class I genes was performed using human alloantisera. Induction by murine alpha interferon of the expression of class I molecules was required to obtain unambiguous identification of these molecules which appear serologically identical to the HLA-B7 and HLA-AW24 molecules expressed at the surface of human peripheral blood lymphocytes of 20 unrelated individuals. Analysis of the transformed cells with 8 different anti-HLA class I monoclonal antibodies results in the definition of 3 separate clusters of antigenic determinants shared by all HLA class I molecules. These studies further suggest the existence of locus-specific serological reactivities associated either with the HLA-A or with the HLA-B and C gene products.

Extensive sequence homologies between Y and other human chromosomes

Twenty-six human Y-chromosome-derived DNA sequences, free of repetitive material, were used to probe male and female genomic blots. We present data from a detailed analysis and chromosomal location of the bands detected by such probes, which demonstrate extensive DNA sequence homology between the mammalian sex chromosomes and autosomes. Under stringent conditions, nine Y-derived probes reacted exclusively with the Y chromosome, 12 probes detected homologous sequences present on both the Y and the X, four probes detected homologies between Y and autosome(s) without any X counterpart and, finally, one probe hybridized to homologous sequences on Y, X and autosome(s). These data are consistent with the hypothesis of a common evolutionary origin for the mammalian sex chromosomes and reveal structural similarities between Y-located and autosomal non-repetitive sequences.

Human XX males with Y single-copy DNA fragments

In humans, XX maleness is the best known example of a sex reversal syndrome occurring with an incidence of one XX male among approximately 20,000 to 30,000 newborn boys. The karyotypes of the majority of these individuals are apparently normal, with respect to the numbers and structure of the chromosomes, but is in contradiction with the phenotypic sex which they display. XX maleness may be either a non Y-related mechanism triggered by a mutation on another chromosome or could be the result of the expression of some cytogenetically undetectable Y chromosome material present in the genome of such individuals. Recently, a number of human Y-specific single copy probes have been isolated. In this study, using several of these Y-specific probes we definitively demonstrate the presence of Y-chromosomal material in the genome of some 46,XX human males. These XX males carry only a fraction of the human Y chromosome. In the three positive cases reported here, presence of inclusive overlapping chromosomal fragments has been detected, implying a genetic heterogeneity of these patients.

Direct hybridization of sorted human chromosomes: localization of the Y chromosome on the flow karyotype

A method is described for directly hybridizing a small number of sorted chromosomes with specific DNA probes. The chromosomes are analyzed by flow cytometry and sorted by deflecting the droplets containing the desired chromosomes onto a nitrocellulose filter. By using probes specific for the human Y chromosome, it has been possible to unambiguously identify the peak corresponding to the Y chromosome in the flow karyotypes of a variety of male cell lines. The position of this peak was found to vary significantly from individual to individual, correlating with the heterochromatin chromosomal polymorphism of the human Y chromosome. The sensitivity of the hybridization was such that, with a probe for a male-specific repetitive sequence, only 2,500 sorted chromosomes were enough to obtain a clear, positive signal; 10,000 were needed with a probe specific for a weakly repeated (maximum, 3-fold) sequence of Y chromosome. With this new method, chromosome sorting may be a rapid and efficient way to assign DNA sequences to chromosomes.

Identification of a viral antigen recognized by H-2-restricted cytolytic T lymphocytes on a murine leukemia virus-induced tumor

Monoclonal antibodies were produced against protein p30, a structural protein of murine leukemia viruses (MuLV) coded by the gag gene of MuLV. Three monoclonal antibodies of different isotypes (i.e., IgG-1, IgG-2a, and IgG-2b) were chosen for extensive analysis. These three antibodies bound to mouse tumor cells induced by Friend, Moloney, Rauscher, and Gross MuLV, but not to noninfected normal mouse spleen cells. The ability of these monoclonal antibodies to inhibit cytolytic T lymphocyte (CTL) activity by masking the antigens recognized by CTL on the target cell surface was studied in various CTL systems. It was found that the only CTL that were consistently inhibited in their lytic activity came from BALB.B (H-2b) mice immunized against syngeneic Gross MuLV-induced B.GV cells. These results thus showed that a subpopulation of BALB.B anti-Gross MuLV CTL recognized a Gross MuLV gag gene product expressed on the surface of B.GV cells.

Identification of a viral antigen recognized by H-2-restricted cytolytic T lymphocytes on a murine leukemia virus-induced tumor

Monoclonal antibodies were produced against protein p30, a structural protein of murine leukemia viruses (MuLV) coded by the gag gene of MuLV. Three monoclonal antibodies of different isotypes (i.e., IgG-1, IgG-2a, and IgG-2b) were chosen for extensive analysis. These three antibodies bound to mouse tumor cells induced by Friend, Moloney, Rauscher, and Gross MuLV, but not to noninfected normal mouse spleen cells. The ability of these monoclonal antibodies to inhibit cytolytic T lymphocyte (CTL) activity by masking the antigens recognized by CTL on the target cell surface was studied in various CTL systems. It was found that the only CTL that were consistently inhibited in their lytic activity came from BALB.B (H-2b) mice immunized against syngeneic Gross MuLV-induced B.GV cells. These results thus showed that a subpopulation of BALB.B anti-Gross MuLV CTL recognized a Gross MuLV gag gene product expressed on the surface of B.GV cells.

Single-copy DNA sequences specific for the human Y chromosome

Detailed studies of the role of the mammalian Y chromosome in primary sex determination are limited by the lack of available specific markers and by the fragmentary knowledge of its molecular organization. Y-derived unique DNA sequences could provide powerful analytical tools to probe directly the structure of the Y chromosome and provide a means of searching for specific expressed sequences. We report here the construction of a partial cosmid library of the human Y chromosome. From independent clones we have isolated 30 unrelated DNA probes that are free of highly repetitive sequences, and have examined their reaction pattern on male and female genomic blots. Of the 30 probes tested, six were specific for the Y chromosome. In addition, four probes gave a male-female differential hybridization pattern and the remaining 20, although Y-derived, reacted similarly with both male and female DNA.

HLA class I genes integrated into murine cells are inducible by interferon

In human cells treated with interferon, there is an increase in the amount of HLA-A, B, C mRNA and, to a lower extent, membrane-bound antigen. However, the mechanism of this mRNA enhancement is still unknown. Using mouse L cells transfected with a unique class I HLA gene, we were able to show that both the related HLA mRNA and protein are increased after murine but not human interferon treatment. Moreover, the discrepancy between interferon-directed HLA mRNA and protein enhancement is also observed. The mouse transfected cells allowed us to study more precisely the origin of this discrepancy.

A glycolipid antigen associated with Burkitt lymphoma defined by a monoclonal antibody

The antigen defined by a rat monoclonal antibody directed to a Burkitt lymphoma cell line was identified as globotriaosylceramide [Gal alpha (1 leads to 4)-Gal beta (1 leads to 4)-Glc beta (1 leads to 1)-ceramide]. The antibody demonstrated a strict steric specificity since it did not react with globoisotriaosylceramide [Gal alpha (1 leads to 3)-Gal beta (1 leads to 4)-Glc beta (1 leads to 1)-ceramide], the positional isomer of the antigen associated with the Burkitt lymphoma. Chemical analysis of various Burkitt lymphoma cell lines revealed that the Burkitt lymphoma cells contained more than 100 times as much of the glycolipid antigen as was found in other human lymphoma and leukemia cell lines.

Presence of an abnormal beta 2-microglobulin mRNA in Daudi cells: induction by interferon

Human alpha and beta interferons increase the amount of class I human histocompatibility messenger RNA HLA-A, B, C and beta 2-microglobulin in most human cells studied to date. This report concerns the effect of interferons on the Burkitt lymphoma-derived cell line Daudi, which does not express HLA-A, B, C antigens or beta 2-microglobulin on its membrane. HLA-A, B, C messenger RNA present in Daudi cells is increased by both alpha and beta interferons. Furthermore, we have shown that although it was not possible to detect mature beta 2-microglobulin protein in the cytoplasm or on the cell membrane of Daudi cells, a poly A+ messenger RNA is present in Daudi cells, which hybridizes with a cDNA clone specific for human beta 2-microglobulin. This abnormal messenger RNA is, however, increased normally by interferon. These effects were also observed with human interferon beta on a variant of Daudi cells characterized by a markedly reduced sensitivity to anti-proliferative and anti-cellular effects of human interferon alpha.

[Presence of 2 different epitopes on the human beta 2-microglobulin defined by monoclonal antibodies]

Two monoclonal antibodies recognizing monomorphic determinants on class I antigens of MHC were characterized. They were shown to recognize beta 2m by cytotoxicity inhibition studies. The epitopes recognized were different, as assayed by cross-inhibition and phylogenetical studies. One antibody recognized free as well as HLA-associated beta 2m. The other reacted with a conformational epitope which was well conserved during evolution.

Preferential effect of gamma interferon on the synthesis of HLA antigens and their mRNAs in human cells

Interferons produce a variety of biological effects on cells. They induce resistance to virus proliferation, inhibit cell growth, modify cell structure and differentiation, stimulate some immune functions and inhibit others. However, the different interferon (IFN) species may vary in their mechanism of action and, hence, in their relative efficiency for inducing each of the effect. IFN-gamma (type II) appears to show stronger immunoregulatory and growth inhibitory effects than antiviral effects, but this conclusion has been challenged in other reports. The aim of the present work is to compare the action of IFN-gamma and other (type I) interferons on the induction of (2'-5') oligo(A) synthetase which is probably part of the antiviral response and the induction of the histocompatibility HLA-A,-B,-C antigens. We have shown previously that the induction of both proteins is regulated by interferons at the mRNA level, but show here that IFN-gamma from stimulated human lymphocytes and from monkey cells transfected by cloned human IFN-gamma cDNA induced the HLA-A,-B,-C and beta 2-microglobulin mRNAs or proteins at concentrations over 100 times lower than those needed to induce the (2'-5')oligo(A) synthetase and the antiviral state. This difference was not found with IFN-alpha and -beta (type I).

[Effect of interferon on human cell lines which do not express class I transplantation antigens: K 562 and Daudi. Presence of a pseudo-messenger RNA of beta 2-microglobulin in Daudi cell line]

Human alpha and beta interferons increase the rate of class I human MHC antigens mRNA HLA-A, B, C and beta 2-microglobulin (beta 2m) in most human cells studied so far. The present work studies the effect of those interferons upon cell lines which do not express class I antigen on their membrane: K 562 et Daudi. If beta 2m mRNA is enhanced in K 562 cell by both alpha and beta interferons, those interferons are not able to promote the de novo synthesis of HLA-A, B, c mRNA, which is not detectable in this cell line. On the other hand, HLA-A, B, C mRNA, which is present in Daudi cell, is amplified by both alpha and beta interferons. Furthermore, we could show that, if it has not been possible to detect mature beta 2m protein either in the cytoplasm or on Daudi membrane, there is a poly A+ RNA in it, which hybridizes with a cDNA probe specific for beta 2m.

Effects of H--Y antigen on morphologic and endocrine differentiation of gonads in mammals

The effects of H--Y antigen, released in a soluble state by male human Burkitt lymphomas and mouse teratomas, were studied in the fetal gonads from 13 to 21-day-old rats and 98-day-old calves, using histologic techniques, radioimmunoassays for testosterone, and bioassays for Müllerian-inhibiting substance (MIS). Whereas no effect was detected in the younger gonads, some structural changes were observed in bovine and 21-day-old rat ovaries when cultured for 5 days with Daudi and male teratoma supernatants, but there was no synthesis of testosterone or MIS. These observations raise questions concerning the critical period of sensitivity to H--Y antigen of female gonads, and the dissociation between morphologic and biochemical events.

A five-generation family with sacral agenesis and spina bifida: possible similarities with the mouse T-locus

In man, a malformation that recalls some of the defects associated with T/t mutants in the mouse is sacral agenesis. We report on a family with a high incidence of sacral malformation, ranging from a complete absence of the sacrum (SA), with or without spina bifida aperta, to a spina bifida occulta (SBO) that could only be detected by x-ray. The condition appeared in a man with four children who were all affect, and thereafter, to varying degrees, in 17 of his 28 descendants. Segregation analysis has been performed in this family, using the Elston and Stewart transmission probability model [1971]. The two traits (SA and SBO) were first studied separated and then together. A fully penetrant major dominant gene is show to cause SA. When the phenotypes SA and SBO are considered together, Mendelian transmission is rejected. This could be explained genetically by two alternative hypotheses: genetic heterogeneity or a dominant major gene transmitted in excess by heterozygotes (tau Aa A = 0.896), suggesting a segregation distortion property of an allele at a T-like locus.

A new Epstein-Barr virus negative Burkitt's lymphoma derived cell-line. I. Analysis of cell surface markers and abnormal expression of HLA antigens

CHEV, a new Epstein-Barr virus negative Burkitt's lymphoma derived cell line has been studied. Karyotype analyses demonstrated the t (8; 14) characteristic translocation. Cell surface characterisation of this line showed the presence of mu and chi immunoglobulin chains and beta 2-microglobulin and the absence of the complement receptor. We are unable to detect HLA--A, B alloantigens on the cell surface which was in contrast with an apparently normal expression of these antigens in the cytoplasm.

A monoclonal antibody with anti-Burkitt lymphoma specificity. I. Analysis of human haematopoietic and lymphoid cell lines

38-13 is a hybridoma-produced monoclonal rat IgM which appears to define a Burkitt's lymphoma-associated antigen (BLA). In this paper, we described the reactivity of 38-13 with a panel of human haematopoietic and lymphoid cell lines. In indirect immunofluorescence (IF) assays, 15 of 26 Burkitt's lymphoma (BL) lines studied were clearly stained with 38-13 (from 13 to 100% positive cells) by microscope, with varying numbers of heavily labelled cells. In these positive cell lines, fluorescence-activated cell-sorter (FACS) analysis demonstrated that BLA was actually present on all the cells. Positive BL included Epstein-Barr virus (EBV) genome-carrying lines and EBV-negative ones; thus, BLA is not related to the presence of EBV. Most of the 15 BL cells that reacted with 38-13 contained a typical t(8;14) translocation, but had variant translocations such as t(2;8) and t(8;22). The cells were derived from BL patients of different geographical origins and clinical features. Four BL lines were poorly stained and seven were negative with 38-13 in IF assays. The 32 EBV-positive lymphoblastoid cell-lines (LCL) studied were negative. In three line pairs, consisting of a tumor line and an LCL from the same patient, only the BL line was demonstrated to react with 38-13. A series of non-BL cells, including haematopoietic, lymphoid and solid tumor lines, all failed to react with 38-13. Various attempts to modulate the expression of BLA on BL cells were unsuccessful. However, it cannot be ruled out that BLA is actually a transient B-cell differentiation marker.

Surface markers on mouse cells transformed after exposure to HeLa chromosomes are Mycoplasma membrane proteins

Antisera were raised against HeLa cells and mouse cells transformed after exposure to HeLa chromosomes (ME-ch.HeLa). The antisera were positive in indirect immunofluorescence assays on both HeLa and ME-ch.HeLa cells, but were negative on normal mouse cells. Immunoprecipitation of 125I-labelled cell extracts showed that Me-ch.HeLa cells contain at their surface 3 proteins of apparent molecular weights of 185,000, 105,000 and 45,000 daltons, which were also present on the surface of our HeLa cells but not on other mouse cell lines tested. However, further study has shown that these proteins are not normal constituents of HeLa plasma membranes but are in fact surface proteins of Mycoplasma orale.

Interferon-dependent induction of mRNA for the major histocompatibility antigens in human fibroblasts and lymphoblastoid cells

In human cells treated with interferons, there is an increase in the amount of HLA-A,B,C and beta 2-microglobulin exposed on the cell surface. We have used a cloned HLA-A,B,C cDNA probe to demonstrate by molecular hybridization that this effect of interferon is preceded by a large increase in the amount of HLA mRNA in the cell. This effect was found in five different human cell lines, with purified leukocyte and fibroblast interferons. The increase in HLA mRNA is comparable in its kinetics and dose-response to the induction of (2'-5') oligo(A) synthetase mRNA by interferons. Therefore, interferons seem to activate at least two cellular genes which have different biochemical functions.

Monoclonal antibodies as a tool for phylogenetic studies of major histocompatibility antigens and beta 2-microglobulin

The cross-reactivity of several monoclonal antibodies recognizing monomorphic determinants of human HLA-A, B, C, and DR antigens and human beta 2-microglobulin (beta 2m) has been studied on peripheral blood leukocytes in 24 different species. An monoclonal HLA-A-, B-, and C-specific antibody and four monoclonal HLA-DR-specific antibodies cross-reacted with cells from all the primate species tested. Furthermore, antibodies HLA-DR-specific were positive with peripheral blood leukocytes (PBL) from cows, goats, sheep, horses, and dogs. Two monoclonal beta 2m-specific antibodies, which were positive with PBL from certain primates, also reacted with cells from cows, goats, sheep, horses, and dogs. Two other beta 2-m-specific antibodies reacted only with PBL from chimpanzees. No reaction could be detected with all our reagents in other classes tested (birds, reptiles, amphibians, and Teleostei).