Modulation of costimulatory molecules CD80/CD86 on B cells and macrophages by stress proteins GroEL, GroES and DnaK.

The aim of this study was to evaluate the effect of the Heat Shock Proteins GroES, GroEL and DnaK on the expression of the costimulatory molecules CD80/CD86 in B cells and macrophages. The interactions among these molecules are able to highly influence the immune response through the regulation of cytokine liberation which, on their own, are able to regulate the immunological response by a feedback mechanism. Our results showed that, on B cells, GroES and GroEL stimulated the expression of CD86 but did not induce the increase of the CD80 expression. CD86 peak expression showed a peak after 24-48 h of culture and decreased 60h after the stimulation. GroES and GroEL also stimulated the expression of CD80 and CD86 on macrophages. The same HSPs did not modify the expression of CD80 and CD86 on cells having characteristics of activated macrophages, the A-THP-1 cell line. DnaK did not induce any increase in the expression of CD80 and CD86 on lymphocytes or macrophages.

Interactions between bovine endothelial cells and Pasteurella multocida: association and invasion.

We investigated the association and the invasion of a bovine aortic endothelial cell (BAEC) line by Pasteurella multocida to study the potential role of internalized bacteria and possible intracellular survival during Pasteurella infections. Our data indicate that P. multocida is able to adhere to and to invade BAECs. The density of the bacterial population plays a defined role for an optimal mechanism of interaction between bacteria and cells, as does the incubation period of association and invasion. The optimal bacteria/cells ratio was found to be 100/1, while the optimal infection time was approximately 4 h of incubation. Bacterial internalization was dependent on microfilament and microtubule stability. The invasion ability of P. multocida in the presence of cytochalasin D was reduced by 60%; in the presence of colchicine it was reduced by 97% and in the presence of nocodazole it was reduced by 95%. Our data show that internalized P. multocida did not induce mortality of invaded endothelial cells. Some Pasteurella cells were able to survive and undergo exocytosis.

Porins and lipopolysaccharide from Salmonella typhimurium regulate the expression of CD80 and CD86 molecules on B cells and macrophages but not CD28 and CD152 on T cells.

OBJECTIVE: The aim of this study was to evaluate the effect of porins from Salmonella typhimurium on costimulatory molecules such as CD80/CD86 and CD28/CD152. The interactions between these molecules are able to influence the immune response through the regulation of cytokines release which, on their own, are able to regulate the immunological response by a feedback mechanism. METHODS: S. typhimurium strain SH5014 (a rough lipopolysaccharide (LPS) producing strain) was used as the source of porins and LPS. Peripheral blood mononuclear cells were obtained from healthy adult donors. THP1 cells were obtained from ATCC (Rockville, MD, USA). Immunofluorescence and flow cytometry were performed using a FACS IV (Becton-Dickinson, Mountain View, CA, USA). RESULTS: Our results show that porins of S. typhimurium increase the expression of CD86 and the expression of CD80 both on B lymphocytes and macrophages, while the expression of CD28 and CD152 on T lymphocytes was unaltered. The expression of CD80 and CD86 is dose-dependent and starts after 24 h post treatment, peaks at 48 h and goes back to the basal value after 72 h. CONCLUSIONS: S. typhimurium porins are able to induce a high expression of costimulatory molecules (CD80 and CD86) on lymphocytes and macrophages.

Lipoteichoic acid and muramic acid modulate the expression of CD80/CD86 on THP-1 cells and CD28/CD152 on Jurkat cells.

The aim of this study is to evaluate the effect of lipoteichoic acid (LTA) and muramic acid (MA) on costimulatory molecules CD80/CD86 on THP-1 cells and CD28/CD152 on Jurkat cells. The interactions between these molecules strongly influence the immune response through the regulation of cytokine release which, on its own, is able to regulate the immunological response by a feedback mechanism. Our results show that LTA and MA regulate expression of CD86 on macrophages while the expression of CD80 remains unmodified. LTA and MA increase the expression of CD86 on THP-1 cells, a macrophage cell line. MA increased Jurkat T cells CD152 expression.

Coinfection with BHV-1 modulates cell adhesion and invasion by P. multocida and Mannheimia (Pasteurella) haemolytica.

Viruses are thought to facilitate bacterial infections of the respiratory tract. The present study shows the effect of BHV-1 on Pasteurella multocida and Mannheimia haemolytica adherence and invasion of MDBK cells. The virus-infected MDBK cells become more susceptible to the adherence of both species of Pasteurella. The observed adherence increase depends on the length of virus pre-incubation time and on virus concentration. When MDBK cells are not infected with virus, they are only invaded by P. multocida, while M. haemolytica is not able to penetrate. The viral infection favours also the invasion by M. haemolytica.