Application of the electroprecipitin test to the detection of the virus of canine distemper

Résumé La production d'un anticorps contre le virus de l'encéphalite canine a été démontrée par électroprécipitation sur l'acétate de cellulose dans une dilution de 18. Une bande de précipitation bien définie a été obtenue dans un intervalle de temps très court, ce qui indiquerait que le test pourrait servir à l'identification de l'antigène encéphalitique chez les chiens suspectés d'en être atteints.

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The author wishes to thank Dr. C. M.Sheldon of the Eli Lilly Co. for performing the serum neutralization test. This work was supported in part by PHS Research Grant No. FR00437-01A1 from the Animal Resources Branch of the Division of Research Facilities and Resources.     

Experimental immunity against trypanosomiasis

Summary 9 groups of 6 female rats were used in an experiment using fraction 3 ofTrypanosoma rhodesiense. 500 g gave 100% immunoprotection and 1000 and 1500 g gave 66% immunoprotection when challenged with 5×10² T. brucei. 2 groups of 10 female rats were tested for a short period inoculation immune response. In this, 750 g of fraction 3 ofT. rhodesiense gave 70% immunoprotection when challenged withT. brucei.I thank the University of Zambia for support; Dr M. A. Q. Awan, Mazabuka, Zambia, forT. rhodesiense andT. brucei; Prof. J. W. Kibukamusoke, Dr O. Okong'o and Dr W. W. Anokbonggo for advice; Mr L. Nyaliti for technical help.     

Loss of virulence of canine distemper virus is associated with a structural change recognized by a monoclonal antibody.

The monoclonal antibody (mAB) L1, which binds to the nucleocapsid protein of canine distemper virus (CDV), was shown to bind to avirulent CDV obtained after serial passages in Vero cells, but not to two different virulent demyelinating CDV-strains propagated in dog glial cell cultures. However, when both virulent CDV-strains were passaged through Vero cells they expressed, after a number of passages, an epitope recognized by mAB L1. The occurrence of the L1 epitope appeared to coincide with loss of virulence in animal inoculation experiments.     

RNA-Induced immunity against a rat sarcoma

Resumen Se estudió el efecto del ARN proveniente del bazo de ratas inmunizadas a un sarcoma transplantable (Sarcoma E 100) en el crecimiento del mismo. Se inyectó ARN normal y ARN de ratas inmunizadas a dos grupos de animales 5 días antes de la implantación del tumor, tomándose un tercer grupo como testigo normal. Los animales que recibieron el ARN inmune tuvieron tumores más pequeños que los de los dos testigos (p < 0.01), a los 30 días después del injerto. Se formula la hipótesis de que el ARN inmune posee la información (memoria inmunológica) para transformar una respuesta inmunitaria primaria en secundaria.

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This work was supported in part by a grant from the Consejo Nacional de Investigaciones Cientificas y Técnicas.     

Loss of virulence of canine distemper virus is associated with a structural change recognized by a monoclonal antibody

The monoclonal antibody (mAB) L1, which binds to the nucleocapsid protein of canine distemper virus (CDV), was shown to bind to avirulent CDV obtained after serial passages in Vero cells, but not to two different virulent demyelinating CDV-strains propagated in dog glial cell cultures. However, when both virulent CDV-strains were passaged through Vero cells they expressed, after a number of passages, an epitope recognized by mAB L1. The occurrence of the L1 epitope appeared to coincide with loss of virulence in animal inoculation experiments.     

Structural basis of bacterial defense against g-type lysozyme-based innate immunity

Gram-negative bacteria can produce specific proteinaceous inhibitors to defend themselves against the lytic action of host lysozymes. So far, four different lysozyme inhibitor families have been identified. Here, we report the crystal structure of the Escherichia coli periplasmic lysozyme inhibitor of g-type lysozyme (PliG-Ec) in complex with Atlantic salmon g-type lysozyme (SalG) at a resolution of 0.95 Å, which is exceptionally high for a complex of two proteins. The structure reveals for the first time the mechanism of g-type lysozyme inhibition by the PliG family. The latter contains two specific conserved regions that are essential for its inhibitory activity. The inhibitory complex formation is based on a double ‘key-lock’ mechanism. The first key-lock element is formed by the insertion of two conserved PliG regions into the active site of the lysozyme. The second element is defined by a distinct pocket of PliG accommodating a lysozyme loop. Computational analysis indicates that this pocket represents a suitable site for small molecule binding, which opens an avenue for the development of novel antibacterial agents that suppress the inhibitory activity of PliG.     

Host macrophages are involved in systemic adoptive immunity against tumors

Summary The positive systemic therapeutic results obtained with adoptive transfer of immune spleen cells could not be reproduced in macrophage depleted mice. Thus, host macrophages are involved in systemic adoptive immunity against tumors.This study was supported by the Rijksuniversiteit Utrecht and the Netherlands Cancer Society (Konigin Wilhelmina Fonds, KWF).     

Neutrophils are mediators of antiviral immunity.

The paper presents evidence that polymorphonuclear neutrophils upon stimulation with herpesvirus-induced antigens release a material inhibitory to virus infection. The material does not appear to be identical to type I or II interferon.     

Antitesticular immunity. Role of the basement membrane

Riassunto Gli Autori hanno dimostrato mediante immunofluorescenza la positività immunologica della parete tubulare del testicolo umano, in un caso di azoospermia. Questo reperto si presta ad interessanti considerazioni riguardo al ruolo svolto dalla membrana basale della parete tubulare nelle malattie autoimmunologiche del testicolo.     

CD4<Superscript>+</Superscript> T cell-mediated immunity against prion proteins

The prion protein (PrP(C)) is essential for susceptibility to transmissible spongiform encephalopathies. A specific conformer of this protein (PrP(Sc)) is, according to the 'protein only' hypothesis, the principal or only component of the infectious agent, designated prion. Transmission of prions between species is often inefficient, resulting in low attack rates and/or prolonged incubation times and is ascribed to a 'species barrier' caused by differences in the amino acid sequence of PrP between recipient and donor. In this report, we demonstrate that these differences in amino acid sequence result in presentation of distinct peptides on major histocompatibility complex class II molecules. These peptides result in activation of specific CD4+ T cells which leads to the induction of an effective immune response against foreign PrP as demonstrated by antibody production. Therefore, CD4+ T cells represent a crucial component of the immune system to distinguish between foreign and self PrP.