Induction of T helper 1 response by immunization of BALB/c mice with the gene encoding the second subunit of Echinococcus granulosus antigen B (EgAgB8/2).

A pre-designed plasmid containing the gene encoding the second subunit of Echinococcus granulosus AgB8 (EgAgB8/2) was used to study the effect of the immunization route on the immune response in BALB/c mice. Mice were immunized with pDRIVEEgAgB8/2 or pDRIVE empty cassette using the intramuscular (i.m.), intranasal (i.n.) or the epidermal gene gun (g.g.) routes. Analysis of the antibody response and cytokine data revealed that gene immunization by the i.m. route induced a marked bias towards a T helper type 1 (Th1) immune response as characterized by high IFN-γ gene expression and a low IgG1/IgG2a reactivity index (R.I.) ratio of 0.04. The i.n. route showed a moderate IFN-γ expression but a higher IgG1/IgG2a R.I. ratio of 0.25 indicating a moderate Th1 response. In contrast, epidermal g.g. immunization induced a Th2 response characterized by high IL-4 expression and the highest IgG1/IgG2a R.I. ratio of 0.58. In conclusion, this study showed the advantage of genetic immunization using the i.m. route and i.n. over the epidermal g.g. routes in the induction of Th1 immunity in response to E. granulosus AgB gene immunization.

In vitro effect of cyclosporin A on immunoglobulin production and concanavalin A induced suppression in primary biliary cirrhosis.

The in vitro effect of Cyclosporin A on the regulation of immunoglobulin production was investigated in 16 patients with primary biliary cirrhosis. A significant improvement in concanavalin A induced suppression of IgG and IgM producing cells was observed after prior incubation of mononuclear cells with 300 ng/ml Cyclosporin A for 30 minutes. No effect was seen on spontaneous or pokeweed mitogen induced immunoglobulin production, nor on con A induced suppression if Cyclosporin A was added after 24 hours. Incubation of mononuclear cells with a variable dose of Cyclosporin A showed an effect only at 250-500 ng/ml. Higher and lower doses had no effect. This dose dependent effect of Cyclosporin A is likely to be related to a differential inhibitory effect on T helper and T suppressor cells and may underlie the clinical benefit being observed in current clinical trials.

The effect of prednisolone in vitro on immunoglobulin production in primary biliary cirrhosis.

Immunoglobulin production and its regulation have been investigated in 36 untreated patients with primary biliary cirrhosis and 14 healthy controls. Using a haemolytic plaque assay, the number of cells spontaneously producing IgG or IgM was normal, while in contrast, proliferation of both IgG and IgM producing cells in the presence of pokeweed mitogen was impaired (P less than 0.01). There was in addition a defect of Con A induced suppression of proliferation of IgG and IgM producing cells (P less than 0.01), which was more marked in those with early disease than in those with advanced disease. In vitro incubation of mononuclear cells with prednisolone, 5 X 10(-8) M, corrected the defect of Con A induced suppression, but had no effect on spontaneous or pokeweed mitogen stimulated immunoglobulin production. Prednisolone was only effective if added prior to exposure to Con A. There is anecdotal evidence that corticosteroids may be beneficial in primary biliary cirrhosis and the results of the present study study suggest that further investigation of their role is warranted.

Mononuclear cell complement receptor blockade in primary biliary cirrhosis.

Peripheral blood monocyte and lymphocyte receptors for Fc and C3b fragments were examined in vitro in patients with primary biliary cirrhosis and other chronic liver diseases using sheep red blood cells coated with anti-SRBC IgG1 (to detect Fc receptors) and with anti-SRBC IgM and complement (to detect C3b receptors). The number of C3b receptors detected on 100 monocytes was significantly lower in patients with primary biliary cirrhosis (23.0 +/- 12.0, mean +/- 1 SD) compared with normal controls (57.4 +/- 16.9) and other chronic liver disease (HBsAg negative chronic active hepatitis 62.0 +/- 17.0, alcoholic cirrhosis 50.9 +/- 4.0), while the number of Fc receptors detected on 100 monocytes was not significantly different in all the groups (primary biliary cirrhosis 72.8 +/- 28.6, chronic active hepatitis 74.7 +/- 14.0, alcoholic cirrhosis 58.0 +/- 13.5 and normal controls 69.6 +/- 19.9). When mononuclear cells isolated from normal individuals were pre-incubated with serum from patients with primary biliary cirrhosis before testing their receptor function there was a significant reduction in the number of C3b receptors detected per 100 monocytes (27.6 +/- 10.8) compared with pre-incubation with normal serum (72.0 +/- 18.0). This reduction in C3b-receptor function was again observed when the serum used for pre-incubation was depleted of circulating immune complexes; but when complement was further depleted from these sera, the number of C3b-receptors detected after pre-incubation was similar to normal values (64.0 +/- 11.8). Lymphocyte receptors showed a similar pattern of results. This implies a specific C3b receptor blockade on monocytes and lymphocytes from patients with primary biliary cirrhosis which appears to be because of blocking by serum factor(s) including complement fragments.