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Biomedical subjects

A Mayr

Publications and source records attributed to A Mayr.

31 records · Page 2Linked to original sources

[The smallpox vaccination strain MVA: marker, genetic structure, experience gained with the parenteral vaccination and behavior in organisms with a debilitated defence mechanism (author's transl)].

The MVA virus is a lab virus ideally suited for vaccination of both man and animal which can be differentiated from the known Vaccinia strains by the use of numerous biological markers. Its reduced virulence for the chick embryo, for experimental animals and for man is a particularly characteristic feature. With the exception of chick embryo fibroblasts, the MVA virus grows in cell cultures only abortively. This applies particularly to cells of human origin in which the cytopathic effect and plaque formation are completely missing. The restriction analysis of the DNS of the MVA virus demonstrates that its genetic structure differs from that of the CVA basic virus and other orthopox viruses. In contrast to the WHO reference strain Elstree, the MVA virus has a genome shortened by about 9 per cent. The use of the MVA virus for human vaccination is particularly indicated in persons to be vaccinated for the first time and likely to entail a risk (on account of allergies etc.) because it brings about a state of revaccination without complications. The MVA virus can be administered in intracutaneous, subcutaneous or intramuscular injections. Innocuoursness and successful vaccination have been demonstrated in more than 120000 persons. While other Vaccinia strains, such as the Elstree virus, experience a drastic increase of virulence in the immunosuppressed organism (subjected to whole-body irradiation), the MVA virus cannot be activated not even in this situation.

Animals

Vaccination against pox diseases under immunosuppressive conditions.

Pox diseases, caused either by smallpox virus or zoonotic pox viruses or animals, continue to be of potential danger to a non-vaccinated population. Mass vaccinations will become necessary and will then also be administered to persons with immunological aberrations. The vaccines which are presently used against smallpox cause severe complications in such hosts. In contrast, the attenuated vaccinia virus strain MVA is safe even under the conditions of immunosuppression and is recommended for the production of smallpox vaccines. Because of the special epizootic situations and the numerous immunosuppressive factors present in developing countries, the use of such a safe pox vaccine there is of crucial importance.

Animals

Controlled field trials with oral and nasal immunization against tetanus in humans.

Under field conditions, the comparative effectiveness of oral, nasal and intramuscular vaccination of humans with tetanus toxoid was investigated. The effectiveness was tested by the determination of antitoxin titers with the L+-method. Oral booster vaccination produced only very low and irregular increases in antitoxin titer even at the highest dose of 6,000 Lf toxoid. In the most favourable case following triple oral immunization, a rise from 6.2 to 6.6 I.U. was achieved. Primary oral vaccination failed to stimulate measurable antitoxin production. After nasal booster vaccination with 1,000 Lf toxoid, a ten-fold rise in antitoxin titer was detectable. Following primary nasal vaccination, an average neutralization titer of 1 I.U. was achieved. The results of intramuscular and nasal booster vaccinations were similar although the antitoxin titers were significantly higher after primary intramuscular vaccination than after primary nasal vaccination. The average antitoxin titer amounted to 11.6 I.U. These results indicate that primary and booster vaccination against tetanus by the nasal route is a safe and effective procedure.

Administration, Intranasal

[Vaccinations of animals and human health (author's transl)].

Vaccination of animals may have both positive and negative effects on human health. The negative consequences largely occur with live vaccines. The protection provided by vaccination to animals is taken advantage of for human health in the most diverse ways, both directly and indirectly. Typical examples are vaccination of dogs and cats against against rabies and inoculation against diseases of cattle, horses and dogs in which reoviruses of serotypes 1, 2 and 3 are involved. An important contribution to the protection of human health is also provided by vaccination with inactivated pathogens against leptospirosis and salmonellosis, against stomatitis vesicularis and American equine encephalitis and in developing countries against brucellosis.

Animals

[Experimental investigations on the immunity development in irradiated mice after local and parenteral immunization with tetanus-toxoid (author's transl)].

Using the "tetanus-mouse" model the differences in immunity development between animals exposed to irradiation (300 R and 400 R) and animals not exposed to irradiation after nasal and subcutaneous vaccination was investigated. Immunization was carried out 1, 3, 6 and 10 days before and after exposure to irradiation. Efficacy of immunization was tested by challenge with 10 X LD50 tetanus-toxin and by antitoxin determination with L+-method. The degree of the immune response was dependent on 1. the irradiation dose, 2. the interval between active immunization and the ensuing or preceding irradiation, 3. the mode of vaccination (local or parenteral) and 4. the vaccination dose.

Animals

Oral immunization against pox. Studies on fowl pox as a model.

Oral vaccination against fowl pox is both effective and harmless. A suitable vaccine strain is the attenuated HP-1 strain in the 200th to 400th tissue culture passage. For optimal immunization virus of the 200th to 270th passage level should be applied twice at an interval of 3 to 4 weeks. Vaccination dose should contain 10(7.0)TCID50. Chickens may be effectively immunized already at 5 days. Immunity is against both homologous and heterologous virus and proves equally resistant to oral, cutaneous and intravenous challenge. Protection of mucous membranes of the upper respiratory and digestive tract forms faster than after cutaneous immunization. Compared to conventional fowl pox vaccination, drinking water vaccination facilitates the technicalities of vaccination; there are immunological advantages and risks of complications are avoided. It can therefore be recommended as a model for vaccination against smallpox in man.

Administration, Oral

Sporadic bovine meningo-encephalitis-isolation of a paramyxovirus.

Isolation of a viral agent (107) directly from brain explants of a 15-month-old heifer with symptoms of a sporadic encephalomyelitis is described. The virus shares properties with the paramyxovirus family. It grows in a variety of cell cultures from different species, and induces nuclear and cytoplasmic inclusion bodies in infected cells. Nucleocapsids measuring 17 nm in diameter were found in the nucleus and cytoplasm of these cells when studied electron microscopically, thus indicating a close relationship of the agent to the measles-distemper-rinderpest group. No infectious virus was released from infected cells, although alignment of nucleocapsids was observed beneath the cell membrane, and no hemagglutinating activity could be detected with the methods employed. The 107 agent was compared serologically with parainfluenza viruses type 1, 2 and 3, simian virus 5, mumps and Newcastle disease virus (NDV), two bovine respiratory syncytial viruses and measles/subacute sclerosing panencephalitis, distemper and rinderpest viruses, always using 107 virus infected CV1 cells and antiserum of the different viruses in indirect FA tests. Positive FA reactions were observed only with two sera obtained from SSPE patients with high antibody titer to SSPE virus, and with one rabbit-anti-rinderpest serum. The titers of these sera to 107 virus, however, were significantly lower than those against homologous viruses. Five out of 9 sera from randomly selected healthy cattle showed antibody titers between 1:10 and 1:80 to 107 virus in FA tests. The significance of these results is discussed with respect to the epidemiology of SSPE in children and its possible implication with rinderpest in Europe.

Animals