After subcutaneous injection of hen's ovalbumin or diphtheria toxoid precipitated with aluminum phosphate, the production of antibody, as judged by the presence in the tissues of antibody-containing cells, proceeds partly within the regional lymphatic glands and partly in the granulation tissue surrounding the nodule which develops at the site of injection. The first production of antibody takes place in the regional lymphatic gland and antibody production in the local granuloma becomes apparent only from 14 days onwards (rabbit).
Antibody-containing plasma cells were demonstrated in the local granuloma up to 7 weeks. Antibody-containing cells in the regional lymphatic glands reach maximum numbers at 2 weeks following injection and decrease thereafter to few cells at 5 weeks.
The adjuvant effect of the aluminum phosphate is interpreted as due partly to the delay in absorption of antigen from the local site of its injection which results in prolongation of stimulation of cells within the regional lymphatic glands, and partly to the production of a local granuloma which contains antibody-producing plasma cells.