Local immunity.

1. Antibody nitrogen was recovered from tissue homogenate extracts of experimentally immunized mice. Contents of 0.2 and 0.46 mg/ml in skin, 0.42 to 0.95 mg/ml in spleen and 0.91 to 2.52 mg/ml in the liver were obtained. This represents about 80% of the total nitrogen from inguinal lymph nodes homogenates, around 20% of total nitrogen in the skin, and but 3% total nitrogen from the liver suspensions. 2. Agglutinins to heat-killed Salmonella paratyphosa B. antigens appeared in 3 days following injection into subcutaneous tissues of mice. When sheep cell erythrocytes were used they did not appear until the 6th day. 3. Agglutinins to formolized Salmonella typhimurium antigens appeared in 3 days at the initial inoculation site and in draining lymph nodes when tested by the direct smear agglutination technic. 4. A technic was presented for detection of agglutinins in air dried films and smears of tissues of organs from immunized animals. 5. When animals which had received a single injection of S. typhimurium antigen 16 days previously and who had not circulating antibody titers were re-inoculated, agglutinins appeared in the draining lymph nodes within 3 hours and at the original site in 24 hours after the challenging injection. 6. A capillary tube technic was presented which restricted the dissemination of antigens. This approach indicated that agglutinins appeared in tissue around the end of the tube in 6 days, at a time when agglutinins were not detectable in the serum. 7. A centrifuge tube technic was presented for the demonstration of agglutinins in skin and draining lymph nodes. This confirmed earlier experiments that agglutinins appeared 3 to 4 day in local areas before their appearance in serum. 8. Cellular response in singly injected animals was characterized by a rhythmic rise, fall, and return to normal of mature lymphocytes; reticular lylmphocytes were present before the Appearance of agglutinins, a constant macrophagia, a mild eosinophilia, and mast cell deregulation by the 9th day. 9. Theoretical corroborating cellular evidence of local antibody formation was presented. 10. Evidence for local production of antibody in the cerebri of mice was not conclusive, but did suggest that antibody found in inoculated cerebri was not formed systemically. 11. Agglutinins were produced in vitro from mouse subcutaneous tissues. By using a method for constant aeration of tissues for 3 days, a titer of 1:8 was obtained. 12. The formation of agglutinins to bacterial antigens in mouse connective tissue “blockaded†with India Ink and egg white was not significantly altered. 13. Initial site of injection of mice receiving multiple injections of antigens was more resistant to challenge with virulent homologous organisms than other parts of the body. 14. The initial site of injection in singly inoculated mice protected animals in ranges of 30 to 50L LD50 does of virulent homologous organisms. The protection afforded by inoculated skin in the area of draining lymph was equal to the protection at the site of the initial inoculation. In contrast, the skin inoculated away from the direction of lymph flow has less protection than the area of initial inoculation. 15. The initial site of inoculation offered greater protection to mice from Diplococcus than Salmonella antigens. 16. Cortisone incorporated with antigens (1) prolonged the time for local agglutinin formation; (2) enhanced the appearance of antibodies in the serum, and (3) exerted a depressive effect upon phagocytosis of antigen particles by local macrophages and neutrophiles.