Abstract
The analysis of specific proteins in single cells is described and applied to the determination of immunoglobulins G, A, and M (γG, γA, and γM) in lymphoid cells of the human tonsil. The number of cells containing γA or γM was much less than the number of cells containing γG, but the average cell content of γA or γM was much greater than the average cell content of γG. Similarly, in one child where relatively few cells containing γG were found, the average cell content of γG in those cells was higher than that in the other children. The limit of sensitivity of the method for each of the three immunoglobulins with the antiserums used was less than 10-14 gram of the specific protein.
