SummaryCholera and malaria are major diseases causing high mortality. The only licensed cholera vaccine is expensive; immunity is lost in children within 3 years and adults are not fully protected. No vaccine is yet available for malaria. Therefore, in this study, the cholera toxin-B subunit (CTB) of Vibrio cholerae fused to malarial vaccine antigens apical membrane antigen-1 (AMA1) and merozoite surface protein-1 (MSP1) was expressed in lettuce and tobacco chloroplasts. Southern blot analysis confirmed homoplasmy and stable integration of transgenes. CTB-AMA1 and CTB-MSP1 fusion proteins accumulated up to 13.17% and 10.11% (total soluble protein, TSP) in tobacco and up to 7.3% and 6.1% (TSP) in lettuce, respectively. Nine groups of mice (n = 10 ⁄ group) were immunized subcutaneously (SQV) or orally (ORV) with purified antigens or transplastomic tobacco leaves. Significant levels of antigen-spe-

Studies have shown enhanced survival of ovarian cancer patients in which the tumors are infiltrated with tumor infiltrating lymphocytes and natural killer cells showing the importance of immune surveillance and recognition in ovarian cancer. Therefore, in this study, we tested cellular immunotherapy and varying combinations of cytokines (IL-2 and/or pegylated-IFNα-2b) in a xenograft mouse model of ovarian cancer. SKOV3-AF2 ovarian cancer cells were injected intra-peritoneally (IP) into athymic nude mice. On day 7 post-tumor cell injection, mice were injected IP with peripheral blood mononuclear cells (PBMC; 5 × 10(6) PBMC) and cytokine combinations [IL-2 ± pegylated-IFNα-2b (IFN)]. Cytokine injections were continued weekly for IFN (12,000 U/injection) and thrice weekly for IL-2 (4000 U/injection). Mice were euthanized when they became moribund due to tumor burden at which time tumor and ascitic fluid were measured and collected. Treatment efficacy was measured by improved survival at 8 weeks and overall survival by Kaplan-Meier analysis. We observed that the mice tolerated all treatment combinations without significant weight loss or other apparent illness. Mice receiving PBMC plus IL-2 showed improved median survival (7.3 weeks) compared to mice with no treatment (4.2 weeks), IL-2 (3.5 weeks), PBMC (4.0 weeks), or PBMC plus IL-2 and IFN (4.3 weeks), although PBMC plus IL-2 was not statistically different than PBMC plus IFN (5.5 weeks, p > 0.05). We demonstrate that cytokine-stimulated cellular immune therapy with PBMC and IL-2 was well tolerated and resulted in survival advantage compared to untreated controls and other cytokine combinations in the nude-mouse model.

Experimentation was carried out to study the effect of pairing a stimulus (PS) with UCS presentations, on the rate of extinction of an avoidance response in humans. It was found that extinction was facilitated by any manipulations of the PS which produced a difference between the acquisition and extinction situations. The greater the difference the more rapid was the extinction. The effect of the PS was interpreted through the generalization-decrement hypothesis and it was suggested that the effect of the PS would be replicable when the stimulus was not paired with presentations of the UCS.

Liver regeneration occurs after removal of or damage to a portion of the liver; it leads to restoration of the original liver mass. The activities of three sodium-dependent amino acid transporters--system A, system N and system ASC--were determined during a 5-day period of liver regeneration in the rat. Seventy-percent hepatectomy or laparotomy was performed in pairs of rats; these rats' livers were removed at different time points after surgery. Transport activity was determined through measurement of the Na(+)-dependent uptake of tritiated amino acids by isolated hepatic plasma membrane vesicles. System A activity, as measured by the Na(+)-dependent uptake of 2-aminoisobutyric acid, is increased in the regenerating liver 2 to 24 hr after surgery compared with that of controls. Kinetic analysis of 2-(methylamino)isobutyric acid uptake showed a 100% increase in the maximum velocity of system A transport in the hepatectomized animals with no change in the Michaelis constant, suggesting an increase in the number of system A transport proteins in the plasma membrane of regenerating liver. During liver regeneration, no changes were noted in the transport activities of system N and system ASC as measured by the uptake of glutamine and cysteine, respectively, in the presence of 2-(methylamino)isobutyric acid. Our work suggests that system A performs a unique role in the secondary active transport of its substrate neutral amino acids to meet the metabolic demands of regenerating liver.