The influence of various adjuvants on antibody synthesis following immunization with an hapten.

For the production of specific antibodies to the hapten MATP (4-Amino-1,2,2-trimethyl-phenylphosphonate) in Balb/c mice various non-toxic adjuvants were compared to Freund's complete adjuvant (FCA). For immunization the hapten MATP was coupled to the carrier human serum albumin (HSA). The immunostimulating effect of the synthetic lipopeptides Pam3Cys-OH, Pam3Cys-Ser-Ser-Asn-Ala and different concentrations of the lipohexapeptide Pam3Cys-Ser-(Lys)4 (Pam3Cys = S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-N- palmitoyl-(R)-cysteine as well as of aluminium hydroxide were tested. IgG antibody titers in serum were determined in ELISA. In dose-response studies 50 micrograms Pam3Cys-Ser-(Lys)4 per mouse was the most effective dose with a long period of high antibody levels after the second booster. Pam3Cys-Ser-Ser-Asn-Ala provoked only low antibody titers. Immunostimulation with Pam3Cys--OH did not result in an increased production of specific antibodies. Compared to the control group an enhanced antibody synthesis could be provoked with aluminium hydroxide. However, the increase was much smaller than by using FCA. The lipopeptide Pam3Cys-Ser-(Lys)4 turned out to be a very potent adjuvant. One week after booster injection into mice 50 micrograms of this substance helped to elicit a higher antibody titer than FCA. Hence, as far as the degree of antibody production is concerned, Pam3Cys-Ser--(Lys)4 represents an alternative adjuvant to FCA.     

Inhibitory effect of monoacylglycerol on fatty acid uptake into rat intestinal epithelial cells

We investigated the influence of glycerol esters on oleic acid uptake into IEC-6 cells. Monoolein, especially 2-monoacylglycerol, significantly inhibited the cellular uptake. Although diolein slightly inhibited the oleic acid uptake, triolein, glycerol and monooctanoate had no effect. These results suggest that after lipid digestion in the intestine, long-chain fatty acid uptake may be influenced by another digestive product, 2-monoacylglycerol.     

Induction of opsonic antibodies to the gamma-D-glutamic acid capsule of Bacillus anthracis by immunization with a synthetic peptide-carrier protein conjugate

The capsule of Bacillus anthracis, a polymer of gamma-D-glutamic acid, functions as a virulence determinant and is a poor immunogen. In this study we show that antibodies reactive with the B. anthracis capsule can be elicited in mice by immunization with a conjugate consisting of a synthetic gamma-D-glutamic acid nonamer peptide (gamma-D-glu9) covalently coupled to keyhole limpet hemocyanin. The serum response to gamma-D-glu9 was comprised primarily of IgG antibodies that recognized an epitope requiring a minimum of four gamma-linked D-glutamic acid residues. Antibodies to (gamma-D-glu9) bound to the surface of encapsulated B. anthracis cells and mediated opsonophagoctosis. These findings suggest that anti-capsular antibodies could mediate the clearance of vegetative B. anthracis cells in vivo. Thus, inclusion of an immunogenic capsular component as well as protective antigen in new anthrax vaccines would generate immune responses targeting both the bacteremic and toxigenic aspects of anthrax infection and thus may increase protective efficacy.     

The convulsive activity of white rats after immunization with a conjugate of sidnofen and serum albumin

The influence of white rats immunization by a covalent conjugate of serum albumin with sydnophen on the seizure activity in the single and repeated injections of pentylenetetrazole was investigated. The immunization lowered the seizure activity in single injections of threshold doses, (60 mg/kg) of pentylenetetrazole. The repeated daily injections of the drug in subthreshold doses (30 mg/kg) inhibited the process of "kindling" effects formation.     

Treatment of the enhanced intestinal uptake of glucose in diabetic rats with a polyunsaturated fatty acid diet

Intestinal absorption of most nutrients is enhanced in diabetic rats. We wished to test the hypothesis that manipulation of dietary fatty acids will modify enhanced uptake of glucose in rats with established streptozotocin-diabetes. Chow-fed control rats or animals with one week of streptozotocin-diabetes were continued on chow or were fed ad libitum for three weeks with semisynthetic isocaloric diets containing a high content of either essential polyunsaturated or non-essential saturated fatty acids. The jejunal and ileal in vitro uptake of varying concentrations of glucose was much higher in diabetic than control rats fed chow or the saturated fatty acid diet. In contrast, the enhanced uptake of this sugar was reduced or normalized in diabetic rats fed the polyunsaturated fatty acid diet. Feeding the polyunsaturated fatty acid diet was associated with increased brush-border membrane activity of alkaline phosphatase in diabetic jejunum and ileum, but neither the saturated fatty acid diet nor the polyunsaturated fatty acid diet altered brush-border membrane cholesterol or phospholipids in control or in diabetic rats. Mucosal surface area was similar in diabetic rats fed the saturated fatty acid diet or the polyunsaturated fatty acid diet. Thus, (1) feeding the polyunsaturated fatty acid diet diminishes the enhanced jejunal and ileal uptake of glucose in diabetic rats, and (2) the influence of the polyunsaturated fatty acid diet on uptake in diabetic rats was not explained by alterations in intestinal morphology or brush-border membrane content of cholesterol or phospholipids. This study suggests that manipulation of dietary lipids may play a role in the normalization of the enhanced intestinal glucose uptake in rats with established diabetes.     

The active immunization of the cyclic ewe against an estrone protein conjugate

Four mature, cyclic ewes were given injections (I.M.) of a conjugate of 1,3,5 (10)-estratrien-3-ol-6,17-dione, 6 carboxyoxime bovine serum albumin (immunized ewes) on day 3 after estrus, and at days 10, 20, 40, 58, 91 and 134 after this initial treatment. Six control ewes treated with carrier emulsion alone continued to cycle normally. Three of the immunized ewes failed to exhibit estrus, an associated preovulatory surge of LH and ovulation. One ewe showed 1 abnormally short estrous period and then became anestrus. Injection of an estrone-protein-conjugate at days 3 and 13 after estrus did not appear to interfere with the rate of structural luteolysis of the corpus luteum present, but plasma concentrations of progesterone reached abnormally high luteal phase levels and in 2 ewes failed, subsequently to decline to normal follicular phase levels. Estrone binding capacity rose as early as day 9 after first treatment, and concentrations of LH rose as early as day 14. Subsequently, plasma levels of LH, estrone and progesterone and antisera titer rose; the only significant cross reaction of the antisera was with estradiol 17beta (11.32 +/- 2.80%).