dies are produced more quickly and for a longer period of time. Memory cells are stored in the lymph nodes and spleen and can remain in the body for the life of an individual. If enough memory cells are produced while encountering an infection, these cells can provide life-long immunity against certain diseases. Sources Immune Cells and Their Products. NIAID National Institutes of Health. Updated 2008 October 02.Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Helper T Cells and Lymphocyte Activation.