Abstracts
146
P792
IMM UNOLOGI CAL STUDIES OF HI. A-G SOLUBLE PROTEI NS
P793
HLA-G5 TRANSCRIPT
CONTAININ G INTRON 4 MAY ENCODE
A
SOLUBLEHLA-G ANTIGEN. Kirszenbaum Marek, Marchal Rachel, Bensussan Armand, Dausset Jean, Carosella Edgardo. CEA - DRM - SRHl Laboratoire d'lmmunoradiobiologie, Hopital Saint-Louis, Centre Hayem, I Av Claude Vellefaux, 75010 Paris, France. HLA-G. a non-classical HLA class I gene, is located within the human major histocompatibility complex locus. It has a tissue-specific expression in trophoblasts, where the products of HLA class Jl or HLA class I classical genes are absent. Thus, it has been suggested that HLA-G has a important role in maternal tolerance of the fetal semi-allograft. The aim of our research work was to produce the human trophoblast HLA-G soluble proteins in vitro in Escherichia C
P794 HLA G POLYMORPHISMS
IN SPONTANEOUS ABORTION.
Moreau Philippe, Carosella Edgardo.TO)'f',i::r Magali, Prost Stephane. Gluckman Eliane, DaussetJean.Kirszenbaum Marek, CEA - DRM• SRHlLaboratoire d'Immunoradiobiologie, H6pital Saint-Louis. Centre Hayem, I AvClaude Vellefaux, 75010 Paris. France. The nonclassical MHC class I IILA·G gene is a puta tive gene required for survival of the serniallogenic foetus expressed at the materna-foetal interface and may be involved in protection from maternaJ NK lysis. It encodes membrane bound proteins isofonns of 37 to 39 KD and a secreted fonn was found in supernatants of culwred cytotrophoblasts and choriocarcinoma cell line lEG. HLA-G is transcribed into fOOT alternatively spliced mRNAs HLA-G I, /ILA-G2. I1LA-G3 and HLA-G4 ladring respectively exon1;exon 7 and 3, exons 7,3 and 4; exons 7 and 4. Previously we have demonstrated tbat all of them are present in trophoblasts and at low abundance io peripheral blood lymphocytes; HLA-G4 is absent in cord blood mononuclear cells. Because exoe 5 encodes the transmembrane region of the HLA-G protein none of these transcripts could originate synthesis of a soluble ill..A-G anugen an absence of proteclytic processmg By using RT-PCR amplification, we demonstrated Ihe presence, in peripheral or cord blood mononuclear cells and trophoolasts of a new alternatively spliced mRNA that contains intron4 (HLA-G5). A stop codonin intron 4 at nucleotide 63 prevents translation of exon 5. Thus this transcript might encode for a soluble form of IILA-G protein. These results are relevant in terms of HLA-G immunological functions and production of solublemolecules
P795
IMPAIRED REPRODUCTION OF THE 8rM DEFICIENT TRANSGENIC MOUSE
Franc;:oise Dufosse , Pascale Cracco , Daniele Breviere, Dominique Becuwe , J e an-Ja cque s Hu art. Centre de Transfusion Sanguine, Lille , France .
Nelson Fernandez. Joanne C. Cooper. Matthew T. Sprinks and Gilltan B. Deallry Department of Biological a nd Chemical Sciences. Centra! Campus. University of Essex, Wivenhoe Park, Colcheste r C04 380, England.
HLA G is a non classical HLA class I gene expressed in extravillous cytotrophoblast at the maternal fetal interface . I t plays an important role in huma n pregancy. Up to date , a limited HLA G polymorphi sms have been descr ibed . We h a v e studied the SSCP patterns of HLA G exon 2 a nd 3 i n a group of 50 couples with an h istory o f repeated spontaneous abortions and in a control group of 30 c oupl e s recru i t ed after del i v e ry of uncomplicated preqancies . The nucleotide sequence variation in HLA G indicates that HLA G shows a h igher rate of polymorphi s ms than expected . The HLA G allele frequencies in both groups were compared and will be presented.
Although the B2-m knock out mouse survives well in a se mi-pathogen free and normal environment they consistently show poor fecundrty. Breeding data from crosses between the transgenic male and wildtype females shows that the B,-m deficient mice have a significantly lower frequency of mating than the control group of C57BU6 mice which produced the expected number of litters. In addition the litter size and weaning success of the Brm deficient mice were lower than the control. Perinatal lethalrtyof the B2-m offspring was also inflicted by the B,·m deficient female by ca nnibalism of Ihe young pups. This behaviour was consistent over a long period of time and was not observed among a- m. t: female mice or wild-type C57BU6 male or female mice housed together. Taken together this data is conslstent with the notion that the 8 r m knock out mouse strain has an impaired breeding capactty as compared to the parental C57BU6 mouse strain Since the 8,-m knock out mice lack cell surface expression of MHC Class I products in the adult tissues and at the pre-implantation stage we postulate that B,..mand in tum MHC deficiency might be responsible for lhe poor breeding capacity of the 8,-m deflcrent mice. The mice superovulate well and show a norma l oestrus cycle and can be resc ued by F, heterozygous Bi-rn +!. acquiring a normal breeding pattern. ThUS, the acquisition of an impaired
breeding phenotype as a result of the knock out effect of 8,·m is a true reflection of the immune status of this mouse strain. At present we are investigating at what stage of the re productive Cycle Ihe developme ntal block of these mice occurs. This finding is relevant to the understanding of the role of 8,-m and MHC indevelopment.
P796
FREQUENCYOF HLA ANTIGENS AT WOMEN WITH RECURRENT SPONTANEOUSABORTIONS
Dlmitrovskl xocno H1s tova H mceva Anita . 81agoevsKa Mile nka , Koievs kl Pe rko. Institute ~' bIOOd tran sfUSion SkOPJe. Republ«: of MacedOnia W e have determined HLP.ant.qens from A an d 8
lOCI a t 305 wome n wlt~, s pont a neous rec urre nt a bortion s of U'lkncwn ~tt,)logy Ail of the m nad ne g3t"'e cros s -ma tcn V'I( 'I lymph'JG\1es from Ihe husba nd Tile obta ined HLA an ltgen s freq uen cle, .ve re ccmpareo With those fron-> cWlrol glQUP of r300 healthy persons . We got h,g he r frequency for a nhgens H,-A-88 a nd 8 18 The ant igen 8 8 was oresent With 17 04% (52 patie nts ) correspo ndin q to 13 07% at the control grou p wltn r.r. = 1) 6 an d . 2 = .3 ,2/ Als o anuoen 8 1B was prese nt wrth 12 .13 % (37 patients) cor responomq to / .0.... of the cont rot grou p ...."h r r = 1 , 8~: .2= 885 ;;nd p 0 .005
Our resu tts 00 not snow $ignltlcant differences in the frequenc ies
of HLA a ntige ns tJetween women With rec urre nt s pontane ous a oortions of unkn own 2t ' ~ l og y and tl'le 11e8ilhy control
P797
A "METAANALYSIS" OF SI1JD IES OF 1lIE PHENOTYPIC FREQUENCIES OF
lILA-DR ANTIGENS IN WOMEN WITH RE CURRENT SPONTA....'EOUS ABORTIO NS
Jersild Casper, Christiansen Ole B, Steffensen Rudi, Department of Clinical Immunology. Aalborg Hospital. Aalborg , Denmark
In previous studies, we have found increasing evidence that genes on HLA-DR~DQ haplotypes comprising a DRBI-OI allele or a DRBI-Q3 allele are susceptibility factors f01 unexplained recurrent spontaneous abortions (RSA). In the present study we carried out a combined analysis of all published studies of tbe distrib ution of HLA-DR specificities among C-aucasian women with RSA. 13 relevant studieswere identifiedcomprisinga totalof 1179 RSA patients. Only in two of these studies (including our own) bad HLA-DR typing been carried out by DNA methods. 10 fourAmerican studies no local control group wasincluded but patient data from these studies were compared with previously published population data. The combined RRs werecalculated by tbemethod suggested by Svejgaard et al. (1974). The RR for DRI was 1.5 (95% CIs: 1.2-1.7), p < 10" and for DR4 it was 1.2 (95% CIs: 1.()'1.4). P < 0.05. Wheo the combined analysis was restrictedto 9 studies in which no exclusion of autoantibody-positive patients had been undertaken, the DR3 antigen also became significantly increased among RSA patients with an RR = 1.3 (95 % CIs: 1.11.6). P < 0.01. In conclusion these results comfinnthe hypothesis thathaplotypescomprising HLA-DRI and -DR3 confer susceptibility to unexplained RSA.