[Interrelations between cells of the nervous and immune systems in vitro].

The collaborative character of the immune response requires direct cell- to cell or humoral contacts between the lymphocytes and the cells of mononuclear phagocyte system. The proposed model of direct interrelationship between the cells of the CNS and the immune system throws much light on the morphology of the lymphocyte entry and its recruitment into parenchyma during pathology. The structure, distribution and membrane morphology of the formed in situ rosette-like clusters (containing microglia, as CNS type of mononuclear phagocytes, and syngeneic lymphocytes) was investigated by light and scanning electron microscopy (SEM).

[Isolation of conjugated sera for the immunofluorescence demonstration of swine parvovirus].

High-titer, specific serum against porcine parvovirus was obtained via hyperimmunization of rabbits, with the use of a Bulgarian isolate that had been partially purified after a known, modified technique. A specific, high-titer conjugate was produced for the immunofluorescence diagnosis of porcine parvoviruses. The microscopic observation of the lamellae of cell cultures, treated with the conjugate, revealed the presence of a specific, typically granulated perinuclear (mostly unilaterally) and, in some cases nuclear fluorescence--at negative reaction in the control preparations.

Morphological and physical characteristics of an antigen associated with viral hepatitis type A (Botevgrad antigen).

Immune electron microscopy (IEM) was employed in studying faecal samples of viral hepatitis type A patients and their contacts, in whom the presence of an antigen, differing from the HBsAg, designated as Botevgrad antigen (BA) was proved by the CFT. Particles 25--28 nm in diameter, aggregated by sera positive for the anti-HAAg were established in the faecal samples. The buoyant density of these particles in CsCl was found to be 1.

[Antibody formation in type A viral hepatitis].

Immune response to hepatitis type A antigen (HAAg) was measured by the passive hemagglutination test (PHA) and by the immune adherence test (IAHA). Specific antibodies found by PHA are of the IgM class which indicates a recent exposure to hepatitis A virus. The antibodies found by IAHA reflect the level of postinfectious immune status.

[Development of cellular immunity in patients with viral hepatitis].

The development of cell-mediated immunity (CMI) to the surface antigen of hepatitis B virus (HBSAg) and Botevgrad antigen (BA) was traced in 50 hepatitis patients. Migration inhibition test (MIT) was performed with purified HBSg and AB. Blood samples from every hepatitis patient were obtained at the beginning of the icteric phase, 10 days later and during convalescence.