Biomedical subjects

T van den Berg

Publications and source records attributed to T van den Berg.

9 recordsLinked to original sources

PubMed2005

Ultrastructural changes of the tracheal epithelium after vaccination of day-old chickens with the La Sota strain of Newcastle disease virus.

The progression of tracheal lesions induced by vaccination of day-old specific pathogen-free chicks with the La Sota strain of Newcastle disease virus (NDV) was examined by relating surface changes as observed by scanning electron microscopy with subcellular changes seen by transmission electron microscopy. NDV infection resulted in hypertrophy of goblet cells, their rupture, and the formation of excess mucus. Activation of goblet cells peaked within 4 days postvaccination. Afterward, the activation levels gradually decreased. At the level of the ciliated cells, a marked increase in the proportion of nonciliated to ciliated cells and later an almost complete deciliation of the tracheal surface were observed because a simple squamous to cuboidal epithelium replaced the original pseudostratified epithelium. Fifteen days postvaccination, all epithelial damage was restored. Because the observed vaccination-induced lesions are detrimental to epithelial integrity and function as a barrier against invading microorganisms, they might explain at the ultrastructural level the secondary complications of vaccination with the La Sota strain against NDV.

Animals↗

PubMed2000

Tuberculosis DNA vaccine encoding Ag85A is immunogenic and protective when administered by intramuscular needle injection but not by epidermal gene gun bombardment.

Immunogenicity and protective efficacy of a DNA vaccine encoding Ag85A from Mycobacterium tuberculosis were compared in BALB/c and C57BL (B6 and B10) mice immunized by intramuscular (i.m.) needle injection or epidermal gene gun (gg) bombardment. In BALB/c mice, gg immunization could induce elevated antibody and cytotoxic T lymphocyte responses with plasmid doses 50-fold lower than those required for i.m. immunization. Interleukin-2 (IL-2) and gamma interferon (IFN-gamma) secretion, however, was much lower in gg-immunized than in i.m.-immunized BALB/c mice. On the other hand, C57BL mice reacted only very weakly to gg immunization, whereas elevated Ag85A-specific antibody, IL-2, and IFN-gamma responses (significantly higher than in BALB/c mice) were detected following vaccination by the i.m. route. Antibody isotypes were indicative of Th2 activation following gg injection of BALB/c and of Th1 activation following i.m. injection of C57BL mice. Finally, C57BL but not BALB/c mice were protected by i.m. Ag85A DNA immunization against intravenous M. tuberculosis challenge, as measured by reduced numbers of CFU in spleen and lungs, compared to animals vaccinated with control DNA. Gene gun immunization was not effective in either BALB/c or C57BL mice. These results indicate that i.m. DNA vaccination is the method of choice for the induction of protective Th1 type immune responses with the Ag85A tuberculosis DNA vaccine.

Acyltransferases↗

PubMed1994

The role of the spleen in the organ-specific metastasis of murine BW 5147 T lymphomas.

Organ-specific metastasis of tumour cells may result from selective invasion and growth or from selective host cell responses. The present study demonstrates how selective interactions with the host affect the metastatic pattern of two murine T cell hybridoma lines, derived from the BW 5147 thymoma. Upon intravenous inoculation into syngeneic mice BW-14 cells preferentially colonize the kidneys, whereas BW-19 cells metastasize mainly to the spleen and the liver. The organ-specific behaviour of the two cell lines appears to be determined by a differential interaction with the spleen microenvironment. Inoculation of BW-14 cells into splenectomized mice results in increased liver colonization, indicating a negative effect of the spleen on BW-14 tumour development in the liver. Macrophages are likely to be involved in this inhibition, since inoculation of BW-14 cells into macrophage-depleted mice also leads to increased liver and spleen metastasis. In contrast, inoculation of BW-19 cells into splenectomized mice results in decreased liver metastasis, which indicates that the spleen exerts a stimulating effect on BW-19 cells. Macrophages also appear to be involved in this stimulation, since macrophage depletion causes a similar decrease in liver and spleen colonization. Hence components of the splenic microenvironment, probably macrophages, exert inhibiting or stimulating activities on BW-14 or BW-19 cells respectively, thereby determining the subsequent liver or kidney colonization.

Animals↗

PubMed1985