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Administration of 5 mg of cyclophosphamide per day for 4 days into neonatal chicks resulted in suppression of natural agglutinin titers up to at least 12 weeks of age. When the administration of cyclophosphamide was delayed until 7 days post-hatching suppression was found up to 8 weeks but titers rose to normal by 10 weeks after initial injections. Injections of cyclophosphamide after 21 days of age did not suppress natural agglutinin titers unless the drug was administered daily for 2 or more weeks.

Human C5a des arg was isolated from complement-activated serum by immunoadsorption followed by Sephadex G-75 chromatography. C5a des arg obtained by this 2-step procedure was shown to be immunologically identical to C5a des arg purified by a conventional multi-step method, homogeneous on SDS-polyacrylamide gels, and biologically active. Although this technique yields approximately the same amount of C5a des arg/liter of activated serum as that obtained by conventional methods, its simplicity and relative rapidity make it a practical alternative.

SummarySera from inbred SPF White Leghorn chickens at 6 weeks or 19-22 months of age did not have anti-OA agglu-tinins as determined by the passive HA reaction; 2-day-old chicks also lacked the anti-OA activity. Inbred chickens kept in SPF isolators for 6 weeks, then transferred to a conventional environment for 7 weeks, produced anti-OA agglutinins. Inbred White Leghorn adult chickens conventionally reared had a high anti-OA agglutinin titer. It appeared that natural anti-OA agglutinins are elaborated in response to environmental pathogens in certain lines of chickens. The titer in the individual chicken appeared as early as 10 weeks and was maintained until old age. The presence of natural anti-OA agglutinins did not prevent egg-laying but appears to have delayed it.The HA reaction is specific and can be absorbed.We wish to thank Dr. E. L. Hodapp for valuable assistance during the course of this investigation, and Dr. L. R. Draper for critical review of the manuscript.

SummaryThe sensitivity of the passive hemagglutination reaction was increased considerably by repeated freezing and thawing of antigen-coated erythrocytes. Cells were stabilized by pyruvic aldehyde followed by formaldehyde and then coated with antigen at low pH. After the desired HA titer was attained, the cells were stored in liquid nitrogen. Antigen-coated cells stored at 20° gradually deteriorated during the course of 18 months.

SummaryPassive cutaneous anaphylactic-like (PCA-like) reaction could be elicted in the skin of newly hatched and young chickens with chicken antiserum. The reaction occurred within 20 min following antigen injection, reacted specifically with the antiserum, and the reaction could be prevented with antihistamine. The present findings indicate that differential susceptibilities to anaphylactic reaction exists depending on the developmental stage of the chicken.

SummaryTested by the Schultz-Dale Technic, chicken antibody failed to sensitize the chicken or the guinea pig intestine. Rabbit antibody sensitized guinea pig intestine but failed to sensitize chicken intestine. The minimum doses of histamine and acetylcholine required for contraction of the chicken intestine were considerably larger than those required for guinea pig intestine.We wish to thank Dr. W. E. Vannier for critical review of the manuscript and Mr. H. Crilly and Mr. B. Clark for technical assistance.

SummaryPCA reactions are seldom elicited in conventional adult chickens in contrast to the positive reaction that are readily obtained in young and specific pathogen free (SPF) chickens. Adult germfree chickens also gave postive PCA reactions. Blood exchange experiments were performed among conventional adult chickens, young and SPF chickens. Conventional adult chickens became PCA positive after receiving blood from young or SPF chickens. This suggests that a factor exists in the blood of young and SPF chickens that facilitates the PCA reaction.

SummaryThe sensitivity of the passive hemagglutination reaction was increased considerably by subjecting stabilized rabbit erythrocytes to periodate oxidation, repeated freezing and thawing, or to low pH prior to coating with the antigen BSA. Cells were stabilized by pyruvic aldehyde followed by formaldehyde and then coated with antigen at low pH.

Effects of N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP), the synthetic chemotactic peptide, and its analogues on blood pressure were investigated in the rabbit, rat, mouse, dog, cat and guinea pig. The administration of FMLP (5 micrograms/kg i.v.) induced the depressor effect in the rabbit but no effect was observed in the other animal species. The only peptide which showed a similar effect as FMLP was N-formyl-L-methionyl-L-methionyl-L-phenylalanine (FMMP) among the peptides relating to FMLP. Tachyphylaxis was observed in the hypotensive action induced by the two peptides.

SummaryA reverse passive hemagglutination (RPHA) procedure was developed for the detection of hepatitis B virus associated antigen (HB Ag) in human serum. The comparative sensitivity of six different methods was double agar diffusion

SummaryThe adjuvant effect of colchicine was investigated in the hamster primarily because this species is unique in tolerating high dosage of colchicine. Administration of non-toxic doses of colchicine enhanced hemagglutinin response, but the increase in antibody response was no greater than that reported for the rabbit, a species far more susceptible to the toxicity of colchicine. The increased level of hemagglutinin was for complete antibody; levels of incomplete antibody were not elevated. Increase in the dose of colchicine to near-lethal levels resulted in considerable reduction in antibody response.