The effect of Syntex adjuvant formulation (SAF-m) on humoral immunity to the influenza virus in the mouse.

Syntex adjuvant in its microfluidized form (SAF-m) was equal to or superior to Freund's complete adjuvant in stimulating an enhanced hemagglutination inhibition (HI) antibody response in mice to trivalent influenza virus vaccine (TIV). There was an average 16-fold increase in HI titer for the three components of the vaccine with no significant differences among strains. The increased serum antibodies correlated with an increase in protection against infection. The threonyl-MDP (t-MDP) component of the adjuvant played no role in this activity. The vehicle, in contrast, was so effective that it could be diluted 1:202 (in the presence of (t-MDP) and still retain a statistically significant effect. Vaccine and adjuvant could be stored together at 4 degrees C for 2 years without a statistically significant change in potency. Mice were given a priming immunization with TIV, PBS, or adjuvanted TIV (AIV). A year later, the mice were boosted with heterotypic TIV or AIV. The nature of the priming immunization made no difference in the strong antibody response to an AIV boost. However, priming significantly improved the response to TIV with AIV being the best primer. The enhancement in the antibody response to AlShanghai of the unprimed (PBS) elderly mice caused by AIV (14-fold improvement over TIV) was similar to that in young mice. Female mice had antibody titers which overall were 2.6-fold higher than those of males (P < 0.0001) for AIV and TIV.

Relevance of the guinea-pig necrotic inflammation footpad reaction to safety concerns with MDP-based adjuvants.

The guinea-pig necrotic inflammatory reaction described by Nagao and Tanaka was investigated to determine its possible relevance to tuberculin-positive individuals who may receive MDP-based adjuvants. The reaction was induced by a preparatory footpad injection of Mycobacterium tuberculosis in Freund's incomplete adjuvant (FIA) followed three weeks later by a provocative gluteal injection of muramyl dipeptide (MDP). Increased footpad swelling and necrosis occurred within 24 h. The reaction was also caused to a significantly lesser degree by a gluteal injection of the threonyl-MDP component of Syntex adjuvant SAF-m. Elicitation of the reaction in responsive animals was absolutely dependent on the presence of both FIA and M. tuberculosis at the reaction site. Animals injected in the right footpad with FIA plus M. tuberculosis and in the left footpad with M. tuberculosis alone responded to the provocative injection with necrosis in the right footpad only. The reaction therefore appears to have little potential relevance to the vaccination of tuberculin-positive humans.

A new hamster model for adenoviral vaccination.

Both adult and baby hamsters infected intranasally with human adenovirus type 5 exhibited virologic, serologic, and histologic evidence of infection. When 8-day old hamsters were infected with 4 x 10(6) pfu, concentrations of virus up to 2 x 10(6) pfu/animal were detected in the lung, peaking on day 2. The minimum infectious dose was 1 x 10(3) pfu/animal. This model may be useful in studies of conventional and recombinant adenoviral vaccines for humans.

Site-specific DNA splicing: a general procedure for the creation of a restriction site at a predetermined position in a DNA sequence.

A method is described for creating any of a wide array of restriction sites at a predetermined position in a known DNA sequence. The method utilizes the exonuclease activity of BAL 31 and a specially designed bifunctional oligodeoxynucleotide linker. The desired restriction site is generated when the linker is ligated to those BAL 31-digested DNA fragments which end with the target sequence. The proper ligation product is then identified by a highly specific hybridization procedure. The method is versatile and specific and is especially useful in the isolation of functional elements of a gene.

Lincomycin increases synthetic rate and periplasmic pool size for cholera toxin.

Increased enterotoxigenicity of Vibrio cholerae 569B grown with low concentrations of lincomycin, previously described in terms of increased extracellular biological activity (capillary permeability factor and fluid accumulation in ligated rabbit ileal loops), was further characterized. Polyacrylamide gel electrophoresis and single radial immunodiffusion showed that lincomycin-stimulated cells produced increased molar quantities of cholera toxin (CT) both extra- and intracellularly. The intracellular CT was released in comparable amounts by sonication, deoxycholate extraction, and polymyxin B treatment. Polymyxin B release of CT was nearly complete under conditions wherein only 6% of total cellular beta-galactosidase was released, implying a periplasmic pool of CT in stimulated cells. No intracellular choleragenoid (CT subunit B) was found in stimulated cells by polymyxin B release. No proteolysis of 14C-labeled CT was detected after prolonged incubation with sonicated nonstimulated cultures or sonicated concentrated cells. These data support the conclusion that the stimulatory effect of lincomycin involves an increase in the rate of synthesis of the CT molecule, and argue against alternative models involving inhibition of putative normal degradation of CT, increased release of otherwise cell-bound CT, or activation of inactive, or less active, forms of CT.