[DNA polymorphism: comparison of allelic frequencies obtained with two HVR probes in a population from Northeastern Brazil and in two other ethnic groups]

DNAS from 325 individuals representing 2 different populations (234 Brazilians and 91 Asiatics) were analysed for Restriction Fragment Length Polymorphisms (RFLPs). These DNAs were digested with Pvu II enzyme and successively hybridized to two HVR probes: alpha globin-3'HVR and Mucin-HVR. An allele frequency distribution was determined for each couple probe/enzyme and each ethnic groupe studied. The results were compared with frequencies observed in french population and we showed that there is no statistic significant difference between allele frequencies obtained with the couple probe/enzyme 3'HVR/Pvu II in Brazilian and French populations. We also showed that both populations studied (Brazilian and Asiatic) do not follow a Hardy-Weinberg balance.

Absence of HIV DNA sequences in seronegative polytransfused thalassemic patients

The risk of infection with human immunodeficiency virus (HIV) by transfusion is not totally eliminated, since contaminated blood given before seroconversion to HIV is not detected on the actual biological screening. We used the polymerase chain reaction (PCR) assay (with one primer pair in the gag region and two in the pol region) to detect HIV DNA sequences in 30 seronegative polytransfused thalassemic patients and in 60 seropositive individuals (used as positive controls). We did not observe PCR-positive HIV-antibody-negative results in seronegative polytransfused patients.

Failure to detect evidence of human immunodeficiency virus type 1 (HIV-1) infection by polymerase chain reaction assay in blood donors with isolated core antibodies (anti-p24 or -p17) to HIV-1

Individuals with isolated and persistent core antibodies (anti-p24 or -p17) to HIV-1 are sometimes diagnosed through the systematic screening of blood donations. The significance of such serum reactivities remains unknown. Polymerase chain reaction (PCR) is a new technique allowing the direct detection of HIV-1 DNA in blood samples. In this study, PCR was used to detect HIV-1 DNA in 20 individuals with isolated and persistent core antibodies (14 anti-p24 and 6 -p17), in seven sexual partners of these individuals, in 55 HIV-1-seropositive individuals (positive controls), and in 105 HIV-1-seronegative blood donors at low risk of HIV-1 infection (negative controls). No HIV-1 DNA was detected in individuals with isolated and persistent core antibodies, in their sexual partners, or in negative control individuals, although PCR was positive in 54 of 55 seropositive control individuals. These results strongly suggest that individuals with isolated and persistent core antibodies are not infected with HIV-1.

Molecular cloning and protein structure of a human blood group Rh polypeptide

cDNA clones encoding a human blood group Rh polypeptide were isolated from a human bone marrow cDNA library by using a polymerase chain reaction-amplified DNA fragment encoding the known common N-terminal region of the Rh proteins. The entire primary structure of the Rh polypeptide has been deduced from the nucleotide sequence of a 1384-base-pair-long cDNA clone. Translation of the open reading frame indicates that the Rh protein is composed of 417 amino acids, including the initiator methionine, which is removed in the mature protein, lacks a cleavable N-terminal sequence, and has no consensus site for potential N-glycosylation. The predicted molecular mass of the protein is 45,500, while that estimated for the Rh protein analyzed in NaDodSO4/polyacrylamide gels is in the range of 30,000-32,000. These findings suggest either that the hydrophobic Rh protein behaves abnormally on NaDodSO4 gels or that the Rh mRNA may encode a precursor protein, which is further matured by a proteolytic cleavage of the C-terminal region of the polypeptide. Hydropathy analysis and secondary structure predictions suggest the presence of 13 membrane-spanning domains, indicating that the Rh polypeptide is highly hydrophobic and deeply buried within the phospholipid bilayer. In RNA blot-hybridization (Northern) analysis, the Rh cDNA probe detects a major 1.7-kilobase and a minor 3.5-kilobase mRNA species in adult erythroblasts, fetal liver, and erythroid (K562, HEL) and megakaryocytic (MEG01) leukemic cell lines, but not in adult liver and kidney tissues or lymphoid (Jurkat) and promyelocytic (HL60) cell lines. These results suggest that the expression of the Rh gene(s) might be restricted to tissues or cell lines expressing erythroid characters.

[Interviews with HIV seropositive subjects identified at the time of blood donation: consequences for pre-donation interviews]

This study is based upon an interview with 31 individuals recently detected human immunodeficiency virus (HIV) seropositive through the systematic screening of blood donations. The location of the blood donation, the type of blood donor, the risk of HIV infection, were established. Questions dealt with the use of blood donation as a diagnosis test and on the notion of an oral or written self-exclusion before the blood donation. The majority of the individuals had a classical risk factor of HIV infection and had given blood for serological testing. This data can allow an adaptation of the medical interview preceding the blood donation to the present epidemiological context of HIV infection.

DNA amplification of HIV-1 in seropositive individuals and in seronegative at-risk individuals

We assessed the HIV-1 status of seropositive and seronegative at-risk individuals by the polymerase chain reaction. Fifty-four out of 55 HIV-1-seropositive samples scored positive. However, HIV-1 proviral DNA was not detected in 16 seronegative homosexuals, 20 seronegative polytransfused haemophiliacs and 20 seronegative thalassaemic children, 20 individuals with isolated and persistent anti-core antibodies and 74 seronegative blood donors. These data indicate that positive HIV-1 DNA is likely to be an exceptional phenomenon in HIV-seronegative people.

ABO-blood-group-related idiotypic network: mimicry of oligosaccharide epitope by rabbit antiidiotypic antibodies to murine monoclonal anti-A antibody

The idiotypy of antibodies (Ab) specific for oligosaccharide determinants of blood groups of the human ABO system was studied through a cascade. Xenogenic antiidiotypic Ab (Ab2) raised in rabbits to the murine monoclonal anti-A61 (Ab1) were screened for reactivity with various anti-ABH Ab. Three anti-A and three anti-A,B monoclonal antibodies (mAb) which were developed in the same mouse strain as that producing Ab1, as well as a human polyclonal anti-A, were found to share cross-reactive idiotopes (CRI) with Ab1. CRI on murine mAb could be due to a Biozzi recurrent Id on anti-A Ab reacting with anti-Id "à la Oudin", while CRI on human anti-A Ab suggested the presence of paratope-induced anti-Id. Inhibition by Ab2 of haemagglutination of A, B or O human red blood cells by many murine anti-ABH mAb, and by polyclonal or monoclonal human anti-A, strongly supported the occurrence of anti-Id mimicking ABH epitopes belonging to type 2 determinants carried by human erythrocytes. Furthermore, a rabbit immunized with Ab2 produced a potent Ab3 response characterized by anti-H-type-2 specificity. Altogether, these results are consistent with the first successful production of anti-Id Ab that mimics the tridimensional shape of a well defined and strictly carbohydrate epitope, eliciting a haemagglutinating Ab3.

[Perpropionic and peracetic acids destroy HIV in suspension, but do not inhibit the virus in contaminated units of blood]

The virucidal activity of peracetic and perpropionic acids was evaluated against HIV in an attempt to inactivate the virus which might contaminate blood units collected from donors. The results showed first that doses of peracids as weak as 50 ppm were able to kill the virus in free suspension, but that the doses that did not adversely affect blood components did not inactivate the virus in those components.

Production and characterization of human monoclonal antibodies against core protein p25 and transmembrane glycoprotein gp41 of HIV-1

With a view to obtaining human monoclonal antibodies against HIV-1 antigens we used the Epstein-Barr virus immortalization technique to induce lymphoblastoid cell lines from peripheral blood lymphocytes of 10 people who were seropositive for HIV-1 and had no clinical symptoms. A number of polyclonal lines were obtained which synthesized antibodies against most of the major proteins and glycoproteins of HIV-1. Three stable clones were characterized for class, secretion characteristics and specificity. Two of these clones produce antibodies which react with gp41, and the third reacts with p25. One of the anti-gp41 antibodies was found to have neutralizing activity.

[Prediction of the clinical course of AIDS in a cohort of 77 seropositive persons. Importance of p24 antigen in the blood and the level of serum IgA]

Among the HIV-1 seropositive subjects detected through blood donation in Paris area who every six months voluntarily went through a thorough clinical and biological follow-up in the Institut National de Transfusion Sanguine, a cohort of 77 subjects had completed at least four biannual controls by september 1988. Upon inclusion in the study, all subjects were CDC stage II or III, none had received any treatment. Biological parameters in entrance in the study were assessed in a attempt to forecast the CD4 lymphocyte count decrease during the 18 months follow-up time. Multivariate forward stepwise analysis indicated that only p24 ag level, IgA level, and partially neopterin or Beta-2-Microglobulin levels were independently predictive of CD4 count at the end of the follow-up and of the CD4 loss at the same time. The prediction by these biological parameters is a rather poor one, 39% of the variation of CD4 lymphocyte count or 30% of the variation of CD4 loss after 18 months of the cohort follow-up being explained. In conclusion, HIV-infection seems to possess an intrinsic evolution which escapes our surveillance by biological parameters.

HLA-associated susceptibility to acquired immune deficiency syndrome in HIV-1-seropositive subjects

No difference in HLA-A, B or DR gene frequencies could be observed between 172 control subjects and 180 HIV-1-seropositive subjects of European ancestry diagnosed through the systematic screening of blood donations. In contrast, progression to acquired immune deficiency syndrome (AIDS; 21 patients) or CD4 lymphocyte loss equal or more than 20% over a 6-month period (37 subjects) was found to be associated with the B8DR3 haplotype (relative risk = 10.64, p less than 0.003, and 2.23, p less than 0.092, respectively). Other independently significant associations assessed through the multivariate Cox proportional-hazards model were B16, BW21 and B35 alleles as factors of bad prognosis. Conversely, A11 and DR4 alleles were factors favouring longer survival.

[Evaluation of the cytotoxicity of two capping materials: in vitro cell culture study]

Evaluation of the biocompatibility of a crown reconstruction material in vivo on human teeth by histologic observation of pulpal reactions is a long lasting and expensive procedure. Before to start it, a first examination can be done by testing the material on cell cultures. If the used culture cells contain antibiotics, it is necessary to combine these tests with a bacteriologic examination of the tested material. Two calcium hydroxide containing materials for dentin-pulp capping, were submitted to cytotoxicity tests using human pulpal fibroblasts cultures. The cytotoxicity of one over the two materials could be related to its lability and bacterial contamination.

A serologic study of red cells and sera from 18 Rh:32,-46 (RN/RN) persons

The red cells (RBCs) and sera from 18 RN/RN persons were studied. The study confirmed the Rh type D+C+E-c-e+Cw-, which is characterized by an increased expression of the D antigen; a markedly decreased expression of the C and e antigens; the presence of a low-incidence antigen, Rh32; and the absence of a high-incidence antigen, Rh46, which is associated with an epitope recognized by a murine monoclonal antibody (MR432). Other Rh antigens of low and high incidence were investigated, and the presence of Rh17 and Rh44 on the RBCs was confirmed. Three persons exposed to Rh:46 cells by pregnancy or transfusion (or both) had anti-Rh46. This antibody gave positive reactions with all RBCs of common and rare Rh phenotype except Rhnull, and those of D--, D.., DCw-, and RN homozygotes. This antibody is considered to be of clinical significance in case of transfusion or pregnancy.

Human liquid bone marrow culture in serum-free medium

Prolonged in vitro maintenance of human bone marrow progenitor cells was achieved using a serum-free (SF) liquid culture system. Culture medium was based on Iscove's medium supplemented with bovine serum albumin, human transferrin, bovine insulin, soybean lecithin, cholesterol, hydrocortisone and alpha-thioglycerol. Under these standardized culture conditions, CFU-GM were maintained for up to 4 weeks, as is the case when using conventional serum-dependent medium. Erythropoiesis exhibited a slower decline than that found using serum containing medium. Development of normal haematopoiesis was effective in spite of poor stromal cell development--a confluent adherent layer as classically described in serum conditions was never achieved. Our newly defined system provides a reliable technique for studying human haematopoietic stem cell proliferation and differentiation in vitro; it allows for rational utilization of currently available purified recombinant growth factors. It may be a promising tool in the clinical use of cultured haematopoietic stem cells.

[DNA amplification using the polymerase chain reaction method applied to the detection of HIV-1 in seropositive subjects and in seronegative subjects at risk]

Polymerase Chain Reaction (PCR) allows the amplification of specific segments of Human Immunodeficiency Virus (HIV) genome. This technique is of interest for direct detection of HIV-1 DNA sequences in peripheral blood mononuclear cells. In our study, 54 out of 55 HIV-1 seropositive subjects were found positive with PCR assay. No detection of HIV DNA was observed in 36 seronegative at risk subjects (16 homosexuals and 20 polytransfused haemophiliacs), in 20 subjects with isolated and persistent anti-core antibodies, in 20 thalassemic polytransfused children and in 74 HIV seronegative blood donors (negative controls). These results are consistent with those of classical HIV serology and indicate that latent HIV-1 infection in seronegative at risk subjects is not a frequent event, if it exists.

[The erythrocyte phenotype Rh: 32,-46: transfusional and obstetric importance]

The red blood cells and sera from 21 RN/RN individuals were studied. The study confirmed the Rh type D+C+E-c-e+, CW-, characterized by an increased expression of the D antigen, a markedly decreased expression of the C and e antigens, the presence of a low incidence antigen (Rh32) and the absence of a high incidence antigen (Rh46) associated with an epitope recognized by a murine monoclonal antibody (MR 432). Four individuals exposed to Rh46 cells by pregnancy and/or transfusion had an anti-Rh46 antibody. This antibody gave positive reactions with all red blood cells of common and rare Rh phenotype except Rh null, D--, D.., DC(W-) and RN/RN cells. This antibody is considered to be of clinical significance in case of transfusion or pregnancy.

Characterization of the blood group Kell (K1) antigen with a human monoclonal antibody

A human monoclonal anti-Kell (K1) antibody secreted by an Epstein-Barr virus (EBV)-transformed B-cell line was used for binding studies and immunopurification of the K1 blood group antigen. The 125I-labeled antibody bound to 4 to 5 x 10(3) and 2.5 to 3 x 10(3) antigenic sites on K1K1 and K1K2 erythrocytes, respectively, with an affinity constant of 5 x 10(8) mol/L-1. Immunoprecipitation analysis showed that the K1 antigen is carried by a 93 Kd glycoprotein containing several cysteine residues, and approximately six N-glycosidically linked sugar chains but no detectable O-linked sugar. A minor labeled component of 32 Kd was also immunoprecipitated from K1K1 RBCs but the 93- and 32-Kd components were absent from K2K2 and Kell null erythrocytes. Under nonreducing conditions, three bands were detected at 200 (weak), 120, and 93 Kd. We suggest that the 120-Kd component represents a heterodimer of the 93- and 32-Kd proteins covalently linked by disulfide bridge(s). The 93-Kd glycoprotein is a transmembrane component which interacts with the membrane skeleton but is distinct from band 3 as shown by one-dimensional peptide mapping. The site density of K1 antigen blood group on Gerbich-negative RBCs (Ge:-2,-3) was threefold lower than on K1K1 erythrocytes, but the qualitative properties of the 93-Kd component were not modified.

PL2-49, a monoclonal antibody against glycoprotein IIb which is a platelet activator

PL2-49 is a murine monoclonal IgG1 antibody obtained after immunization of Balb/c mice with EDTA washed platelets. Binding could be detected on Zwa(+) as well as Zwa(-) platelets, but not on type I Glanzmann's thrombasthenia platelets using an ELISA screening test. Immunoprecipitation studies showed that PL2-49 bound to glycoprotein IIb when the glycoprotein IIb/IIIa complex dissociation was performed after the monoclonal antibody binding. Experiments with a human alloantibody against Zwa antigen were run in parallel to control the complex dissociation. Ascitic fluid, as well as the purified antibody, induced activation and aggregation of washed platelets and ATP release. PL2-49-induced aggregation did not require exogenous fibrinogen and was inhibited, partially, in the presence of aspirin, apyrase, isosorbide dinitrate. Raising intra-platelet cyclic AMP with a stable PGI2 analogue, iloprost, and/or a phosphodiesterase inhibitor, RA 233, suppressed the responses to PL2-49. F(ab')2 fragments did not induce aggregation of normal platelets but inhibited the response to the whole immunoglobulin. Finally PL2-49 was shown to induce aequorin-detected elevations in intraplatelet Ca++ levels. Thus PL2-49 seems to differ from monoclonal antibodies so far described, since it binds to glycoprotein IIb in a complex-dependent manner at least under our experimental conditions for immunoprecipitation studies, and it induces platelet Ca++ mobilization and platelet aggregation after a lag-time. These reactions depend both on Fab and Fc domains of the antibody and require neither complement nor exogenous fibrinogen.

[Early anomalies of CD4 and CD20 lymphocyte cycles in human immunodeficiency virus]

Circadian variations in the number of circulating lymphocytes and their subpopulations have been observed in healthy subjects. These cyclic changes are characterized by a trough at 8:00 a.m. and a peak at midnight. Using multiple peripheral blood samplings, we were able to confirm that this cycle applied to CD4 T-cells (helpers) and to B-cells (CD20). No cycle of CD8 lymphocytes was observed. In a second stage, for greater comfort of the patient the number of samplings was reduced to two: one at 8:00 a.m. (trough) and one at midnight (peak). This method enabled us to calculate the amplitude of lymphocytes cycles in 18 controls and 74 human immunodeficiency virus (HIV) seropositive patients. In asymptomatic HIV carriers the amplitude of CD4 cycles was normal in 6/26 cases and that of B-cell cycles in 2/17 cases. In the group of asymptomatic HIV carriers the mean amplitude of the cycles was much less reduced than in the other two groups. These results incite us to believe that the loss of the CD4 T-cell cycles is an early sign of HIV infection antedating the decrease observed in the number of these cells.

[Techniques of DNA polymorphisms revealed by probes for the Y chromosome applied to questions of father-son line in analyses of paternity]

The Y specific probe (two 49f and 49a sub-clones) is a polymorphic one for the A (5 alleles), C (2 alleles), D (3 alleles), F (2 alleles) and I (2 alleles). We show that the corresponding allelic combinations, or haplotypes, are transmitted father-to-son in eleven random chosen families. Utilisation of these polymorphisms in other eleven father-son paternitity cases, studied for a panel of erythrocytic and seric markers, shows a good correlation between the two approaches, most of the paternies excluded by the Y probes being also excluded with other allotypic markers. Utilisation of this sort of polymorphism does not necessitate the knowledge of maternal genotype in families studied.