Biomedical subjects

L Chedid

Publications and source records attributed to L Chedid.

221 records · Page 13Linked to original sources

PubMedDate not supplied

[Interferon induced in the hamster by subunits of "Nocardia": essay of protection against rabies (author's transl)].

Lipid-free cells of Nocardia opaca and a cell extract (NWSM) are interferon inducers in syrian hamsters: peak interferon appears 2 h after injection as compared to 8 h in the case of interferon induced by inactivated NDV virus. The interferon induced by Nocardia product is inactivated by a treatment for 30 min at 56 degrees C or 24 h at pH 2: NDV-induced interferon is more stable under these conditions. Hamsters inoculated with NWSM before and after infection with rabies virus are partially protected: their survival time is slightly increased.

Animals↗

PubMedDate not supplied

[Autoimmune aspermatogenetic orchiepididymitis in guinea pigs induced by water-soluble adjuvants].

Use was made of water-soluble adjuvant fractions with homologous sperm, sperm extract or sperm autoantigens to induce autoimmune aspermatogenic orchiepididymitis (AIAO) in guinea-pigs. Guinea-pigs were injected with soluble sperm extract or sperm purified autoantigen S emulsified in incomplete Freund adjvant (IFA) together with two synthetic watersoluble adjuvants, Mur-Nac-L-Ala-D-isoGlu et Mur-Nac-L-Ala-acide D-isoGlu. These animals developed lesions of AIAO, delayed hypersensitivity reactions and specific anti-spermatozoa antibodies. These lesions and reactions were comparable to the ones induced in a control group treated with the same spermatozoa extract or autoantigen S in complet Freund adjuvants. No lesion was observed in the absence of IFA, Other guinea-pigs received a mixture of spermatoza or purified sperm autoantigens, S, P, T. and of polyadenylicpolyuridylic complex either in saline or emulsified in IFA. The recipients of sperm or autoantigen T mixed with Poly A:U, with ou without IFA, displayed lsdions of AIAO; autoantigen S and Poly A:U in IFA, provoked AIAO but did not do it in the absenceof IFA.

Adjuvants, Immunologic↗

PubMedDate not supplied

The effect of a water soluble adjuvant on the immune response to synthetic polypeptides.

The effect of a water soluble adjuvant (WSA) extracted from mycobacteria on the immune response to synthetic polypeptides has been studied in rabbits and inbred mice. WSA increased the antibody response of rabbits to the synthetic polypeptide poly(Tyr,Glu)-poly(DLAla)--poly(Lys) designated (T,G)-A--L when injected together with either incomplete or complete Freund's adjuvants (FIA or FCA). As compared to the respective controls, the effect of WSA was more pronounced when injected with FIA. No detectable antibody titre was observed in rabbits immunized with (T,G)-A--L and WSA administered in an aqueous medium. WSA had no enhancing adjuvant effect on the antibody response of C3H.SW high responder mice to (T,G)-A--L when given either with FIA or with FCA. However, the antibody titres of C3H/HeJ and SJL low responder mice to (T,G)-A--L were increased by WSA when injected in combination with FIA or FCA. The immune responses of mice to two other synthetic polypeptides poly(Phe,Glu)-poly(DLAla)--poly(Lys), designated (Phe,G)-A--L, and poly-(Tyr,Glu)-poly(Pro)--poly(Lys), designated (T,G)-Pro--L, were not affected by the addition of WSA. Thus, WSA "corrects" selectively the genetic defect of low responder mice to synthetic antigens.

Adjuvants, Immunologic↗

PubMedDate not supplied

[Isolation and characterization of mitogens from Nocardia].

Two methods have been devised to isolate mitogens from Nocardia cells. (1) Lysozyme treatment of delipidated cells followed by fractionation of the soluble extract leads to a mitogen devoid of cell wall constituents. (2) Cell disruption followed by differential centrifugations shows that two mitogenic structures are present: the cell wall and fragments of the cytoplasmic membrane. The active component of the cell wall is the peptidoglycan wherefrom soluble mitogenic fractions have been obtained using bacteriolytic enzymes other than lysozyme. An intact glycan moiety seems necessary for mitogenic activity.

Centrifugation↗

PubMedDate not supplied

Relationship between chemical structure and adjuvant activity of some synthetic analogues of N-acetyl-muramyl-L-alanyl-D-isoglutamine (MDP).

Synthetic N-acetyl-muramyl-L-alanyl-D-isoglutamine, hereafter referred to as muramyl dipeptide or MDP, represents the minimal structure which can replace mycobacterial cells in Freund's complete adjuvant. This synthetic adjuvant can also enhance the humoral antibody response when administered to mice with an antigen in water by various routes including the oral route. The present paper reports some new results concerning the relationship between the structure and the adjuvant activity of MDP. Synthetic analogues of MDP were tested either in a water-in-oil emulsion in guinea-pigs or in saline in mice. The chemical modifications concerned essentially the D-glutamyl residue. The results obtained confirm the importance of maintaining the intact structure of the D-Glu residue and show that adjuvant activity can be abolished by certain modifications at the level of both carboxyl functions.

Adjuvants, Immunologic↗