Chlamydophila abortus (Chlamydia psittaci serotype 1) clearance is associated with the early recruitment of neutrophils and CD8(+)T cells in a mouse model

The immune mechanisms in response to Chlamydophila abortus (Chlamydia psittaci serotype 1) infection were studied in C57BL/6 and CBA mice. The infection was monitored and the following aspects of the immune response were evaluated: the nature of the leucocyte infiltrate in the liver, the percentages of polymorphonuclear neutrophils (PMNs), macrophages and lymphocytes in the spleen, and the concentrations of cytokines in serum. In addition, the serum concentrations of IgG1 and IgG2a were determined. Both mouse strains showed a Th1-like immune response, with high concentrations of IFN-gamma and minimal levels of IL-4; however, C57 mice differed from CBA mice in showing milder clinical signs and earlier resolution of infection. The greater ability of C57 mice than CBA mice to eliminate chlamydophilae was related to the establishment of an earlier innate immunity, based on a more pronounced PMN response, and on a greater presence of CD8(+)T cells.

Differences in the immune response against ruminant chlamydial strains in a murine model

CBA/J mice were used in the present study to establish differences between the immune response to three chlamydial strains: AB7 (Chlamydia psittaci wild-type strain), 1B (C. psittaci vaccinal strain) and iB1 (C. pecorum). The evolution of chlamydial infection was evaluated in each strain by studying the clinical signs, the number of bacteria isolated from the spleen and the pathology of the liver. Three aspects of the immune response were then studied: the characterization of the infiltrate of leukocytes in the liver, the percentages of T- and B-cells, macrophages and neutrophils in the spleen, and the presence of cytokines in the serum. Infection followed a different course in the C. psittaci-infected mice; 1B-infected mice showed milder levels in all the parameters analysed than their AB7-infected counterparts. The resolution of infection was earlier in 1B-infected mice and, although the immune response to both strains was Th1-like, a more intense CD8+ T-cell response and an earlier presence of TNF-alpha in serum were observed in this group. C. pecorum infection was controlled mainly by a non-specific immune response, since these mice showed no signs of a systemic specific immune response. Neutrophil depletion experiments showed that these cells play a very limited role in the non-specific response against C. pecorum.

Benefit of switching from a protease inhibitor (PI) to nevirapine in PI-experienced patients suffering acquired HIV-related lipodystrophy syndrome (AHL): interim analysis at 3 months of follow-up

This multicentre, randomized, open-label, prospective trial is evaluating the effects of switching treatment from a protease inhibitor (PI)-containing regimen to one containing the non-nucleoside reverse transcriptase (RT) inhibitor nevirapine in human immunodeficiency virus (HIV)-infected patients with durable viral suppression but suffering from lipodystrophy. Objectives of this ongoing study are to evaluate the effects of this switch on changes in body shape and metabolic abnormalities associated with acquired HIV-related lipodystrophy syndrome (AHL), as well as on maintenance of viral suppression and immunological and psychological effects. Preliminary data involving 57 patients with 3 months of follow-up show an initial improvement of AHL in two regions, the face and arms. There is also a tendency toward improved cholesterol and triglyceride levels and improved quality of life among patients receiving the nevirapine-containing regimen. Maintenance of viral suppression was equivalent in both treatment groups. Additional data with longer follow-up are needed to confirm these results.