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Biomedical subjects

C Pilet

Publications and source records attributed to C Pilet.

At least 37 records · Page 2Linked to original sources

[Activity of polar glycopeptidolipids from Mycobacterium chelonae in the reversal of chemically induced leukopenia in mice].

Intraperitoneal administration of polar glycopeptidolipids extracted from Mycobacterium chelonae (GPLp-Mc) has led to reversal of Doxorubicin-induced leucopenia in a manner comparable to that effected by GM-CSF administered in a dose of 100 IU (2.5 micrograms/kg). The mode of action and the toxicity of this product are being studied. Results obtained on the mouse indicate that it would be worthwhile to undertake tests in man aimed at studying the effect of GPLp-Mc on chemotherapy- and radiotherapy-induced leukopenias, once toxicological studies have been carried out.

Animals↗

Immunomodulatory properties of a strain of Mycobacterium chelonae--II. Qualitative and quantitative stimulation of mouse splenocytes by Mycobacterium chelonae.

Intraperitoneal [i.p.] and subcutaneous [s.c.] administration to BALB/C mice with a single dose of 5 mg/kg body weight (wet weight) of live Mycobacterium chelonae (Mch) augmented splenocyte blastogenesis. Similar increases in splenocyte blastogenesis manifested during a single oral administration to mice with 100 mg/kg body weight (wet weight) of this Mycobacterium. When splenocytes issued from these mice are activated by mitogens, a highly significant enhancement of lymphoblastic transformation was observed. On the other hand, multiple oral administrations with 50 mg/kg body weight (wet weight) to Mch/dose did not manifest statistically significant differences in splenocyte blastogenesis as compared to controls. Meanwhile, a highly increased transformation of splenocytes, issued from such mice, is observed in response to lectins and to the mitogenic effect of this microorganism. Splenocyte counts have shown 44.5, 37.6, and 23.2% increases in response to i.p., s.c. and multiple oral administration of this bacterium, respectively, as compared to solvent controls. Repeated s.c. administration of this mycobacterium manifested short lived and weak syndromes of anaphylactic shock during and immediately after the second inoculation of Mch. This phenomenon is not observed during repeated intraperitoneal and oral administrations. In conclusion, parenteral (i.p. and s.c.) and oral administration of Mch stimulates the immune system of mice. This effect is characterised by increased in vivo cell multiplication and by enhanced ex vivo DNA synthesis of murine splenocytes. The need of further studies is eminent to elucidate classes of immunocompetent cells involved in this phenomenon.

Animals↗

Immunomodulatory properties of a strain of Mycobacterium chelonae. I. Mouse lymphocyte responses in vitro.

Immunomodulatory properties of a strain of live Mycobacterium chelonae (Mch) was investigated in an in vitro lymphocyte transformation system. Murine splenocyte activation by this bacterium was characterized by polyclonal lymphoproliferative responses in a dose dependent fashion. Optimal doses ranging from 20 to 80 micrograms of Mch (wet weight) per ml of cell suspension induced a very significant mitogenic effect. Higher doses (100 micrograms) of Mch manifested a decreased rate of tritiated thymidine ([3H] TdR) uptake whereas responsiveness of splenic lymphocytes to lower doses (0.156 microgram) was not modified. Contrary to the splenocyte responses activation of murine thymocytes by this mycobacterium is characterised by a decreased proliferation as compared to the background count of unstimulated cells. Simultaneous addition of Mch with optimal doses of Concanavalin A (Con A) and Phytohemaglutinin (PHA) potentiated polyclonal mitogenic responses of murine splenocytes to these two lectins. However, proliferation of these lymphocytes to Lypopolysaccharide (LPS) induction was not modified. BALB/C and DBA/2 spenocytes were found to be more responsive to stimulation by this Mycobacterium as compared to those of C3H/Ou and to a lesser degree to those of C57BL/6 mice.

Animals↗

Comparative study of the safety and protective value, in pre-exposure use, of rabies vaccine cultivated on human diploid cells (HDCV) and of the new vaccine grown on Vero cells.

The object of the study is to compare the tolerance and the efficacy of a new inactivated rabies vaccine grown on Vero cells (PVRV), with the vaccine cultivated on human diploid cells (HDCV), using the schedule recommended by WHO for pre-exposure on days 0, 7 and 21. Of students exposed to a risk of rabies at Alfort Veterinary School, 144 volunteers received either HDCV or PVRV vaccine. No student received a booster between the first blood sample before immunization on day 0 and the last antibody titration 21 months after the beginning of immunization. No serious side-effect occurred with either vaccine, although some vaccinees complained of redness, induration or local pain and, exceptionally, of fever. The study indicates the excellent immunogenicity of both HDCV and PVRV vaccines in all vaccinees. The geometric mean of antibody titres shows a higher titre in the PVRV group and a rapid decline in immune response with both vaccines, four months after the first injection, followed by a stabilization of the antibody level throughout the rest of the study. It should be noted, however, that very few individuals were found to be seronegative 21 months after the first injection.

Adult↗

[Cat retroviruses and human retroviruses: elements of comparison].

Following emotional head-lines of certain articles in the press, making believe that the cat could be susceptible to the AIDS virus, the authors present elements of comparison between principal feline retroviruses (the feline leucosis virus and the feline immunodeficiency virus) and the two human immunodeficiency viruses (HIV). The feline leucosis virus in differentiated from the human and the feline immunodeficiency viruses by its virological, pathological and epidemiological characteristics. Being close to the AIDS virus in the taxonomy of retroviruses, the feline immunodeficiency virus (FIV) presents a number of similarities with the HIV. Therefore, the FIV could give rise to interests in its use as a model in the study of AIDS. Whatever the factors of resemblances may be, there are no elements of present knowledge in favor of an inter-species contamination (cat-man); on the contrary, these viruses demonstrate a marked species specificity.

Acquired Immunodeficiency Syndrome↗

Production and control of specificity of a goat anti-bovine thymocytes antiserum.

The identification and the numeration of the lymphocytes in cattle is realized essentially by revealing the membranary properties of these cells: receptors for some lectins (i.e. peanut agglutinin or phytohemagglutinin), receptors for sheep red blood cells (SRBC), surface-specific antigens concerning T-lymphocytes and surface immunoglobulins concerning B-lymphocytes. The technique of the production in the goat of a specific anti-bovine T-lymphocyte antiserum (GABTA) is described. The GABTA shows a specific cytotoxic activity on 55% of the peripheral blood lymphocytes and more than 95% of the thymocytes. It inhibits, at 90%, the formation of the rosetting with SRBC. This reagent allows identification and a common and quick numeration of the T-lymphocytes in cattle.

Animals↗

Exploration of the cellular mediated immunity by the blastogenesis test during chronic brucellosis in human.

The diagnosis of the chronic, human brucellosis is frequently difficult and usually needs experimental methods. This paper describes a lymphocyte stimulation test with a Brucella antigen and the results of this test concerning 45 brucellic or not brucellic patients. It is concluded that this test is interesting, especially for the chronic and sero-negative Brucellosis diagnosis.

Antibodies, Bacterial↗

[Immunocompetence of newborn calves: evaluation of the proliferative response of lymphocytes in vitro to 3 nonspecific mitogens (concanavalin A, phytohemagglutinin, pokeweed mitogen) during the 1st 3 months of life].

A micromethod technique was used to evaluate in vitro sensitivity of the peripheric bovine lymphocytes obtained from a newly born calf, up to 3 months of age to different non-specific mitogens: Phytohemagglutinin (PHA) Concanavaline A (Con A) and Pokeweed Mitogen (PWM). The results obtained show that the calf lymphocytes respond to the 3 mitogens by a considerable cellular proliferation. The blastogenic response was found at various levels during the first 3 months of life, and appeared to stabilize at levels similar to the adult bovine. Highly sensitive variations were noted in the lymphocyte reactivity, notably with PHA and Con A. These results seem to indicate the existence of periods of T cell immunodeficiency, not only during the first few days after birth, but throughout the first months of the calves' life. It may also be indicative of the interest of immunostimulant therapy during this period, which needs further investigation.

Aging↗

Influence of the antigenicity of Brucella preparations on modulation of the immune response to sheep erythrocytes.

The relationship between the expression of surface antigenicity of inactivated Brucella and the immunostimulant properties on the sheep erythrocyte response was studied in mice. The agglutinogenic Brucella abortus B19S preparation was compared to two non-agglutinogenic preparations (B19R and PB), using the plaque-forming and rosette-forming cell tests. When Brucella and antigen were injected together, only non-agglutinogenic preparations, even used at low doses, were able to increase the plaque-forming and rosette-forming cell responses measured 4 days after immunization. When the interval between the previous injection of non-agglutinogenic preparations and that of the antigen increased or when they were injected 24 h after the antigen, the modification of those two responses was no longer observed. After day 4, for the simultaneous injection of Brucella and antigen, B19S and PB preparations induced the best responses; this effect was dose dependent. Thus, in the present experimental situation, the modification of the day 4 response appeared independent of those of the ensuing days.

Agglutination↗

[Effect of temperature on preservation of brucella vaccines].

In the case of B.19 vaccine, the test of seven days conservation at 37 degrees C does not provide any indication of the long-term conservation of this type of vaccine. The variable results are difficult to interpret, except in extreme cases where the tested vaccine has deteriorated. If this test permits to disclose the deficiencies of lyophilization, it does not permit the stability of this strain to be foreseen. Heating for 30 days at 37 degrees C gives better results, without showing any satisfactory correlation with the duration of validity of the vaccine. Further trials need to be undertaken to try to establish a correlation between an accelerated ageing test and the duration of validity of B.19 vaccine.

Brucella↗