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Biomedical subjects

G Wittmann

Publications and source records attributed to G Wittmann.

At least 73 records · Page 4Linked to original sources
PubMed1979

Colostral immunity in piglets from sows vaccinated with inactivated Aujeszky disease virus vaccine.

Neutralizing antibodies against ADV were transmitted from sows, vaccinated with inactivated ADV adjuvanted with DEAE dextran, to their offspring via colostrum. The suckling piglets were protected by colostral immunity against contact infection with ADV at week 1 p.p., however, they were not protected against i.n. infection (10(8) TCD50). At 2 and 3 weeks p.p. all the piglets were protected against both contact infection and i.n. infection. At 4 weeks p.p. 50 per cent of the litter were protected against i.n. infection, in spite of very low antibody titres (1:2--1:4). The colostral antibodies did not interfere with active antibody response when the piglets were vaccinated with the inactivated vaccine from 2 weeks p.p. onward. Lymphocytes from suckling piglets of a vaccinated sow showed in vitro reactivity (enhanced 3H-thymidine incorporation) against ADV and BHK antigen, both contained in the vaccine used for the immunization of the sow.

Animals↗
PubMed1978

[Newly developed virusvaccines in veterinary medicine (author's transl)].

Newly developed vaccines in veterinary medicine can be classified into two categories. The first category comprises inactivated vaccines produced by "classical" methods such as inactivation of the virus by formalin and the use of A1(OH)3 as adjuvant. Besides, this category also includes live vaccines from attenuated virus. Thus, all of these vaccines represent no genuinely new developments and owe their origin to the fact that the importance of several virus diseases of animals has grown in the last years, making neccessary the rapid production of corresponding vaccines. Such virus diseases are infectious bovine rhinotracheitis/vulvovaginitis, enzootic rhinopneumonitis of cattle, virus diarrhoe of calves, rhinopneumonitis of horses, kennel cough of dogs and Marek's disease of chickens. The second category comprises inactivated vaccines which represent genuinely new developments through the use of more efficient chemicals for virus inactivation (ethylenimines) and more efficient adjuvants (oil emulsions, DEAE dextran). Such vaccines were especially developed with regard to foot-and-mouth disease and Aujeszky disease in pigs, where "classical" vaccines are rather inefficient. These types of vaccines are, however, also efficient in other animal species and with other viruses. Entirely new vaccines which are more or less still in an experimental stage are vaccines made from split products of viruses e.g. from glycoproteids of rabies virus, or made from membrane constituents of cells infected with avian herpes viruses.

Adjuvants, Immunologic↗
PubMed1976

Cell-mediated immunity in Aujeszky disease virus infected pigs. I. Lymphocyte stimulation.

The appearance of cell-mediated immunity was studied in Aujeszky diseased pigs with the aid of the in vitro stimulation of sensitized lymphocytes. The first cell-mediated immunity reaction of lymphocytes occurred 4 days after infection. From day 7 to 35, the latest day tested, the reactions were most marked with lymphocytes from lymph nodes and spleen, whereas blood and thymus lymphocytes reacted less frequently; bone marrow lymphocytes showed no response. Reinfection did not considerably enhance lymphocyte reactivity. Humoral immunity was demonstrated a few days later than cell-mediated immunity. Neutralizing antibodies were first detected at day 7, reaching optimal titers at day 14. Complement fixing antibodies were detected from day 14 onward. Reinfection caused a very weak booster effect only on neutralizing antibody production. The sensitivity of the neutralization test could be enhanced up to sixfold by the addition of fresh guinea pig complement. It is concluded that cell-mediated immunity influences the early stage of infection with Aujeszky disease virus when humoral immunity is not yet demonstrable or yet rather low. Lymph nodes and spleen are apparently of special importance for the appearance of ADV-reactive lymphocytes.

Animals↗
PubMed1976

The in vitro effect of diethylaminoethyl dextran on stimulation of mouse lymphocytes, and on the mitogenic activity of concanavalin A and lipopolysaccharide.

Unpurified lymphocytes from spleen, lymph nodes, thymus, and T and B cell-enriched fractions of spleen cells from NMRI mice as well as lymphocytes of nude mice were cultured and stimulation of the lymphocytes by DEAE-D, Con A and LPS and combinations thereof was measured by incorporation of 3H-thymidine. It was demonstrated that DEAE-D is a rather weak mitogen for mouse lymphocytes, acting apparently on B cells as well as on T cells. Frequency and intensity of lymphocyte stimulation by the T cell mitogen Con A and the B cell mitogen LPS was much better. When combinations of DEAE-D with Con A or LPS, respectively, were used significant enhancement of lymphocyte stimulation occurred, as compared to the mitogens and DEAE-D alone. This enhancement was more prominent with the DEAE-D/Con A combination than with the DEAE-D/LPS combination, and more pronounced with the T cell-rich lymphocyte preparations than with the B cell-rich suspensions. The results are discussed and it is concluded that DEAE-D enhances both T cell and B cell functions, however, T cell functions are favoured. This enhancement is assumed to be mediated by a membrane effect of DEAE-D, and to be responsible for th immunological adjuvant effect of DEAE-D.

Animals↗
PubMed1975

Some investigations on the adjuvant mechanism of DEAE dextran.

In vitro it was shown that adsorption of inactivated FMDV onto DEAE-D kieselgur columns did not occur in the presence of 0.1--0.15M NaCl. These NaCl concentrations are present in DEAE-D/FMDV vaccines and in the tissues of animals. Therefore, adsorption of virus antigen does not appear to be responsible for the adjuvant effect of DEAE-D. In pigs it was demonstrated that DEAE-D exerts its optimal adjuvant effect, as measured by the formation of neutralizing antibodies and protection against challenge infection, when injected together with inactivated FMDV as vaccine. Apart from this, a good adjuvant effect (group immunity 75--100 per cent) was evoked in about one half and a moderate effect (group immunity 50--70 per cent) in about a quarter of the inoculated animals even if DEAE-D was separately injected locally and temporally from the inactivated virus. With regard to immunity it apparently does not matter whether DEAE-D or inactivated virus was given first, but an interval of 48 hours or 4 days between injection seemed to be more favourable than one of 24 hours. With regard to the formation of neutralizing antibodies the situation is comparable to that of immunity with the exception that a time interval of 24 hours between the application of DEAE-D and inactivated virus or vice versa was as good as that of 48 hours or 4 days. The results are discussed in regard to the possible mechanism of the adjuvant effect of DEAE-D on the cellular level.

Adjuvants, Immunologic↗
PubMed1975

[Studies on the Relationship between immunity and the level of neutralizing antibodies in pigs vaccinated against foot-and-mouth disease (author's transl)].

The statistical relationship between the titers of neutralizing antibodies and the immunity of 706 pigs vaccinated against FMD was studied. This was done for each of four virus strains separately. Whereas no correlation between both test systems could be detected in case of the strains A5 Westerwald, C Detmold and O1Santander, a significant correlation was ascertained for the strain O1Kaufbeuren. Becuase of the different findings depending on the virus strain under study it was concluded that the antibody titer alone does not provide a useful measure for potency testing of FMD-vaccines for pigs.

Animals↗