Immunodepressive effects of trypanosomal infection in cattle immunized against contagious bovine pleuropneumonia

Abstract

Groups of cattle infected singly with Trypanosoma vivax and T. congolense and, with a combination of T. vivax and T. congolense, were vaccinated against contagious bovine pleuropneumonia (CBPP) 6 weeks before or after infection. All animals were revaccinated 12 weeks after primary vaccination. The primary antibody responses in cattle vaccinated 6 weeks after infection with T. vivax and a combination of T. vivax plus T. congolense were slightly depressed in contrast to other groups which were similar in their response to the control group. Although secondary antibody responses developed in all infected groups, with a delay in those infected with T. congolense, they did not reach the levels of the controls. In spite of the slight depression in antibody responses, however, 50% of the vaccinated trypanosomal animals contracted CBPP on exposure to experimental infection while the vaccinated controls were immune. It is suggested that the protective immunity to CBPP engendered by vaccination is impaired during infection with African trypanosomes and that the level of antibody response to CBPP vaccination in trypanosomal animals does not reflect the degree of immunodepression. The importance of trypanosomiasis control in ensuring success of vaccination campaigns against CBPP is discussed.

Etudes expérimentales sur l'efficacité des souches vaccinales T1 sr et T1/44 de <em>Mycoplasma mycoides</em> spp. <em>mycoides</em> (petite colonie) contre un isolat causant la péripneumonie contagieuse bovine au Kenya - Effet d'une infection de rappel

“…An additional factor can be found in the immunomodulation effect of some parasitic infestation such as liverfluke. This factor has already been mentioned for trypanosomes (6). All these factors may certainly also play a role in the ability of the vaccine to induce a good protection, something which is often overlooked in the field and may explain some apparent vaccination failures.…”

“…Each group was kept in a different house separated by a distance of 40 m. Each group was inoculated by a different strain, group one with the Gladysdale strain which had been traditionally used in former trials, group two with an MmmSC strain isolated in Rwanda in 1994, and group three with a local Kenyan isolate. The Gladysdale strain, originally isolated from Australia, had been kept at NVRC 5 -KARI since 1960 and the field isolate from Rwanda was isolated and characterized by CIRAD-EMVT 6 for the official confirmation of CBPP in that country. For the first two groups, the inoculation was performed intratracheally with 60 ml of an MmmSC pure culture followed by 30 ml of 1% suspension of low melting agar.…”

Immunobiology of African Trypanosomiasis

“…Immunosuppression is a well-characterized feature of trypanosomiasis, both in experimental rodent models [15,16], domestic animals [17] and humans [18]. The effects of trypanosomiasis on the immune system have been extensively studied in experimental mice.…”

Investigating the Impact of Helminth Products on Immune Responsiveness Using a TCR Transgenic Adoptive Transfer System

“…As many of these infections are pandemic, impaired vaccine-induced immunity as a result of concurrent parasitic infections is of huge potential health significance (11)(12)(13)(14), and understanding the mechanisms of the immunomodulation by parasites has obvious consequences for the design of vaccines.…”