Antigens of Amblyomma americanum ticks recognized by repeatedly infested sheep.

Sera were taken from 3 sheep that had been infested 5 times with Amblyomma americanum and that exhibited manifestations of humoral depression to homologous antigens and anti-tick resistance. Proteins extracted from the intestine or salivary glands of unfed ticks or salivary glands from partially (3-day) fed ticks were analyzed by polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate-PAGE. Antigens recognized by the sheep in the same materials before and after each infestation were analyzed by western blots. The sheep responded to 44 antigens. Nine to 23 antigens were recognized by the preinfestation sera and the sera of 2 gnotobiotic sheep. Four antigens (34,000, 36,500, 38,000, and 115,000 MW) were revealed conspicuously by the serum of the first infestation but very weakly or not at all by the sera of the third infestation onward. Two antigens (35,500 and 29,000 MW) from fed salivary glands were revealed only by sera taken after manifestations of resistance had appeared. These antigens may be responsible for anti-tick protection. The 29,900 MW antigen was present also in salivary extracts of Boophilus microplus.

Manifestations of immunity in sheep repeatedly infested with Amblyomma americanum ticks.

Three sheep were infested 4 times with 100 Amblyomma americanum tick pairs and kept indoors until the natural termination of the infestations. Characteristics of the tick populations that show efficiency of feeding, fertility, and offspring development, and ELISA antibodies to tick salivary gland extracts were studied at each infestation. On average, female ticks fed on tick-naive sheep detached at 12.1 +/- 0.2 (mean +/- standard error) days, weighed 492 +/- 16.8 mg, engorged 40.7 mg per day, and 35% survived to detachment during the first infestation. During the fourth infestation, they detached at 17.3 +/- 0.8 days, weighed 321 +/- 14.4 mg, engorged 18.8 mg per day on average, and 23% survived to detachment. On average, oviposition of female ticks fed on tick-naive sheep started at 11.8 +/- 0.6 days of detachment, the egg mass weighed 236 +/- 13.2 mg, 43% of the female weight turned into eggs, and 89% of the ticks that detached survived to oviposition during the first infestation. During the fourth infestation, oviposition started at 15.1 +/- 0.5 days, the eggs weighed 103 +/- 9.9 mg, 13% of the tick weight became eggs, and 67% of the ticks survived to oviposition. On average, eclosion started at 35.4 +/- 0.9 days of oviposition and 83% of the egg batches hatched in the first infestation. During the fourth infestation, eclosion started on day 34.9 +/- 0.7, and 47% of the egg batches hatched. Anti-tick resistance was expressed as an inhibition of feeding, fertility, and offspring development.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunological responsiveness of chinchillas to outer membrane and isolated fimbrial proteins of nontypeable Haemophilus influenzae.

Thin, nonhemagglutinating fimbriae have been demonstrated on 100% of the clinical isolates of nontypeable Haemophilus influenzae recovered from children with chronic otitis media tested in this laboratory (L. O. Bakaletz, B.M. Tallan, T.M. Hoepf, T.F. DeMaria, H.G. Birck, and D.J. Lim, Infect. Immun. 56:331-335, 1988). Chinchillas with induced otitis media responded to this surface-located antigen of both the infecting and a heterologous strain. Antibodies were found in both serum and middle ear fluids.