CELLULAR SITES OF IMMUNOGLOBULINS

The distributions of three kinds of immunoglobulin polypeptide chains, Λ, k and γ were determined in 14 speciment of human lymphoid tissue, 8 spleens and 11 mesenteric lymph nodes, obtained during abdominal operations or at autopsy within 4 hours of death. All of the materials were fixed in 95% cold ethyl alcohol and paraffin sections were prepared. None of the patients had paraproteinemia or blood disease. Fluorescent antibody technique staining with pairs of immunofluorescent reagents, which reacted specifically with k‐, λ‐, and γ‐chains and were labeled with contrasting fluorochromes, were employed. The relative numbers of these cells in tissue sections were calculated. The approximate percentages of k‐ and Λ‐containing cells, 61% and 38% were in accord with the ratio of these types of immunoglobulin in normal serum2–3:l. The percentage of k‐ and Λ‐chain containing cells in IgG globulin and in other immunoglobulins was about 62% and 38%, respectively. Approximately half of all fluorescent immunocytes produced IgG globulin in the lymphoid tissues of spleens and lymph nodes. Immunoglobulin containing cells with k‐, Λ‐and γ‐chains did not differ significantly in size or pattern. They could be plasma cells, medium sized to large lymphocytes or lymphoid plasma cells, and were primarily found in the red pulp of the spleen and medulla of lymph nodes. Single immunocytes and germinal centers did not synthesize both k‐ and Λ‐light chains at the same time.