Effect of passive transfer of human anti-myelin-associated glycoprotein IgM in marmoset.

Adult and one week old marmosets were injected intravenously within a one month period or intraperitoneally within a 6 week period respectively, with monoclonal IgM having an anti-myelin associated glycoprotein antibody activity. No clinical or electrophysiological abnormalities could be detected in experimental animals. However, indirect immunofluorescence studies showed IgM deposition in close contact to myelin sheaths. Minor but distinct alterations of nerves were found in the adult: the enlargement of Schmidt-Lanterman incisures seen in electron microscopy could explain the decrease of the proportion of fibers of small diameter found by morphometry of semi-thin section, and the reduction of the mean internodal length in fibers of a given diameter seen in teased nerve fibers studies.

Production and characterization of a mouse monoclonal antibody to the glycolipid asialo-GM1.

The glycosphingolipid asialo-GM1 (aGM1) is a true differentiation antigen of murine lymphoid cells. This glycolipid is highly immunogenic in the rabbit, but the antisera produced shows some cross reactivity with GM1, the naturally occurring sialylated derivative of aGM1. In the present study we examined the ability to raise anti-aGM1 antisera in the mouse. We compared the efficiency of several immunization methods in various strains of mice. The most effective procedure involved repeated intraperitoneal injections of aGM1-cholesterol rich particles in the NZB mouse. Hybrid B cell lines were generated by fusion of mouse myeloma cells with the splenocytes of an NZB mouse immunized with aGM1. The specificity of the antisera produced and of the monoclonal antibody secreted by one of these hybridomas (103HT30) was defined by ELISA and by immunostaining on thin layer chromatograms. The monoclonal antibody 103HT30 is an IgM. It reacted with aGM1 but not with any of the structurally-related ganglioside or neutral glycolipids tested. In particular, 103HT30 monoclonal antibody did not present any detectable cross-reactivity with GM1.

The SCID mouse.

Numerous investigations of the mammalian hematopoietic system in normal and pathologic states have been facilitated by the study of genetically determined immunologic dysfunctions in experimental animals. This article focuses on the scid mutation of the mouse (SCID mouse) that causes severe defects in the development of the immune system. The mutation appears to impair the recombination of antigen receptor genes, causing in the SCID mice a lack of functional T and B lymphocytes. Other hematopoietic cell types appear to develop and function normally. SCID mice readily support normal lymphocyte differentiation and can be reconstituted with normal lymphocytes from syngeneic or allogeneic mice and even partially reconstituted with human lymphocytes. They also support the growth of allogeneic and xenogeneic tumors. Thus, SCID mice might be useful for studies of both normal and abnormal lymphocyte development and function.

[The marmoset in biomedical research. Value of this primate model for cardiovascular studies]. / Le marmoset en recherche biomédicale. Intérêt de ce modèle primate pour les études cardiovasculaires.

Because of its small size, low cost of maintenance, breeding capabilities in captivity, the marmoset, a New World monkey, appears well suited for clinical and fundamental investigations. The contribution of this laboratory animal in the main areas of biomedical research is succinctly described: viral oncology, infections diseases, immunology, reproduction, toxicology and teratology, odontology, behaviour and neuro-psychopathology. Emphasis is put upon the exceptional interest of the use of marmoset as a biological model in cardiovascular studies.

Plasmodium falciparum: isolation and characterization of a 55-kDa protease with a cathepsin D-like activity from P. falciparum.

Native electrophoresis followed by imprint digest method using hemoglobin as substrate allowed the detection of parasite hemoglobinase activity at acidic pH (3.9 to 5). This protease was inhibited specifically by pepstatin A and insensitive to other protease inhibitors. The molecular weight determination using modified SDS-PAGE followed by imprint digest method, demonstrated a single area of activity at 55-58 kDa, similar to cathepsin D characterized in eucaryotic cells. The parasitic origin has been shown by radiolabeling experiments with [35S]-methionine. The 55-kDa protein was immunoprecipitated by a rabbit anti-cathepsin D serum.

Analysis of DR-like molecules on a marmoset Epstein-Barr virus-induced cell line using a monomorphic anti-human HLA-DR monoclonal antibody.

Mouse anti-HLA D region-related (DR) monoclonal antibodies have been found to cross-react with peripheral blood leukocytes from one primate species, the common marmoset (Callithrix jacchus). Immunoprecipitates of radioactively labeled cells extracted from a marmoset Epstein-Barr virus-induced cell line were analyzed by one- and two-dimensional gel electrophoresis and compared with the DR antigens of a human lymphoblastoid B cell line. Two chains of estimated molecular weights of 34 000 (alpha) and 28 000 (beta), similar to the human alpha and beta chains, have been observed in marmoset immunoprecipitates. Additionally, a set of spots located in the same area as the set of invariant spots found in human HLA-DR antigens is shown by two-dimensional gel electrophoresis. Thus, cross-reacting anti-human HLA-DR monoclonal antibodies could be used to analyze the expression and the structure of marmoset DR-like antigens.

[Polymorphism of HLA genes: I. Demonstration of a close correlation between DNA fragments determined by BglI restriction enzyme and HLA class I antigens]. / Polymorphisme des gènes HLA: I. Mise en évidence d'une étroite corrélation entre des fragments d'ADN déterminés par l'enzyme de restriction BglI et des antigènes HLA de classe I.

Description of DNA fragments associated to HLA class I gene is possible by using restriction enzymes which determine these fragments and specific DNA probes which permit their detection. In one family, with a child presenting a recombination between HLA-A and C, six fragments determined by the enzyme BglI were found to be polymorphic. The informative fragments segregate with HLA, either with a whole haplotype or with one of the two recombinant segments of the HLA complex. In a small sample of population they correlate with one (A11) or with a group of known cross-reactive antigens serologically defined (A3 and A11; A25 and A26. Another fragment is associated with unknown cross-reactive antigens (A2 and A29).

Marmoset red blood cell receptor for membrane-associated complement components is not related to human CR1: partial characterization of the C3-binding proteins responsible for the spontaneous rosette formation between marmoset red blood cells and human leukocytes.

Cells from all the human B-lymphoblastoid cell lines tested and most human monocytes form rosettes with marmoset red blood cells (MaRBC). Because previous reports suggested the involvement of complement components in this phenomenon, the mechanism of rosette formation and the eventual similarities between the MaRBC receptor and the CR1 receptor present on human erythrocytes have been analyzed herein. The binding of MaRBC to human leukocytes strongly differs from the immune adherence phenomenon: rabbit anti-human CR1 did not react with MaRBC and the MaRBC receptor-binding activity is Ca2+-dependent. Rosette formation required intact energy metabolism and cytoskeleton integrity of leukocytes. Our attempts to purify the receptor from MaRBC membranes revealed the absence of CR1. Nevertheless, C3-binding proteins were isolated by selective desorption by Sepharose iC3 column chromatography. A three-band pattern was observed under reduced conditions with 74,000, 70,000, and 53,000 molecular weights. It was not possible to further separate these components. This protein complex inhibited the rosette phenomenon between MaRBC and both Raji and U-937 cells, exhibited a very poor cofactor activity, and had no decay-accelerating activity toward the classical C3 convertase. This material did not cross-react with antibodies directed to human proteins. These results showed that erythrocytes from new world monkeys do not express a receptor analogous to the human CR1, but expressed C3-binding protein with low cofactor activity that could recognize membrane-associated complement components.

The innate resistance of CBA mice to endogenous murine leukaemia virus infection.

The incidence of lymphomata in CBA mice is low and furthermore is unaltered by transplantation at the early blastocyst stage and being born from the lymphoma-prone AKR. The number of C-type murine leukaemia virus particles in CBA derived in this manner and milk-fostered by AKR mice in no way differs from normal CBA. The results suggest that the oncogenic Gross virus does not pass through either the transplacental or transmammary routes, or alternatively that viral replication in the CBA was in some way inhibited. Both possibilities have still to be distinguished.

The influence of parity and maternal preimmunization on fetal survival in mice.

PIP: It is known that as parity increases, cell-mediated immunity to paternal antigens increases in mice. The article reports an experiment designed to compare the results of normal parity with artificial immunization simulating maternal sensitization to paternal antigens in mice. Virgin females were immunized at weekly intervals by intraperitoneal injections of 50 mcl of heparinized blood from males with whom they would eventually be mated. The immunized virgins and multiparous females were mated for 4 to 6 weeks after their last injection or litter. The total and live litter size increased with immunization; the total size with natural parity also increased though the live litter size slightly decreased with parity. The mean fetal death rate was relatively the same for both groups. Fetal weight increased with parity but not change was observed in placental weight. Both fetal and placental weight did not change with immunization. There was no increase in the expected number of male fetuses. The increased litter size in the immunized group may be due to increased ovulation rates.^ieng

Characterization of a human lymphoblastoid cell line permanently modified by simian foamy virus type 10.

Simian Spumavirinae serotype, SFV10, of a Papio cynocephalus baboon, was used to infect a human lymphoblastoid cell line, LV2. Permanent growth and morphological alterations of infected cells occurred, even though no viral particles were detected. Evidence for the presence of viral genomes in the modified cell line is provided indirectly from immunological studies and induction experiments followed by coculture procedures. The permanently modified cell line obtained (LV2-FB10) is an interesting model for the investigation of the possible integration of foamy viruses into the host genomes.

Presence of pH2-sensitive circulating interferon among Callithrix jacchus marmosets.

Significant and relatively stable levels of serum-interferon were demonstrated in a Callithrix jacchus population. This circulating interferon was acid-sensitive in all cases, classifying it as immune or "gamma-type" interferon. Our results in these hematopoietic chimeras suggest that the presence of immune-type or at least pH 2-sensitive interferon could be related to the presence of two allogenic lymphocyte populations in each marmoset.

Interferon inhibits Aspergillus fumigatus growth in mice: an activity against an extracellular infection.

Prophylactic treatment of mice with interferon (IFN) or polyinosinic-polycytidylic acid [poly(I:C)], an IFN inducer, provided significant protection against an extracellular infection by Aspergillus fumigatus in both Swiss and Swiss athymic nude mice. Tunicamycin (TM) treatment inhibits the antifungal activity of IFN and poly(I:C) in these mice. Anti-asialo GM1 or TM [both inhibitors of natural killer (NK) cell function] treatment enhance the severity of A. fumigatus infection. These results suggest that NK cells may play a role in A. fumigatus infection and in the antifungal activity of IFN.

Failure to suppress theta antigenic expression in progeny derived from pre-immunized maternal recipients.

One possible theory concerning the success of the fetus as an allograft has been attributed to maternal modification of foreign fetal antigenic expression. In this respect progeny derived from pre-immunized maternal mouse recipients, have been examined for any modification (reduction) of corresponding theta antigen determinants. Two major groups of mice were examined. The first group of embryo transplantation derived AKR homozygotes born from pre-immunized CBA recipients whilst producing the corresponding anti-thetaAKR antibody activity. The second group of naturally derived reciprocal (CBA x AKR)F1 heterozygotes were also born from pre-immunized maternal recipients. In neither group was theta expression found to be modified and the significance of this finding is discussed in respect of other situations where fetal antigenic expression is known to be altered by maternal influence.

The CD39 molecule defines distinct cytotoxic subsets within alloactivated human CD8-positive cells.

Lymphocyte activation induces or increases the expression of several surface structures, none of which is characteristic of an activated cell subset. In particular, structures such as CD45RO, CD25, CD26, CD49b, CD54, CD71 are expressed by the vast majority of lymphocytes at various times following in vitro activation. CD39 molecules were originally identified on activated B lymphocytes and have recently been described on activated T cell clones. In the present report, we have characterized phenotypically and functionally defined cell subsets generated during an in vitro allostimulation. Results indicated that the percentage of CD39+ cells reached a maximum at day 6 and remained stable thereafter. We demonstrate that CD39 expression allows the identification within the allosensitized CD8+ cytotoxic cells of distinct subsets of cells mediating allo cytotoxic T lymphocyte or natural killer (NK)-like reactivity. More precisely, CD8+CD39+ alloactivated cells mainly mediate specific killer activity, whereas CD8+CD39- alloactivated cells predominantly exhibit NK-like reactivity. Further, we show a high functional correlation associated with the lack of CD39 expression on NK-like alloactivated CD8+ cells, while there is no association with CD56 or CD57 NK-associated structures.