After considering general preliminary immunological aspects, the author discuss the "transfer factor" of Lawrence (TF) which is one of the lymphokines that are produced by the thymus-dependent lymphocytes (LT). This factor whose nature and the probable constituent fractions are also considered, is the initiator of the cellular immunity. In immunodeficiencies, the LT should be stimulated by introducing the TF in the organism (immunotherapy). The possible use of other immunostimulating substances, which could replace the TF (levamisole BCG, thymosine), is also presented. Finally the author emphasize the large perspectives in the use of these factors in Ophthalmology: herpes, uveitis, melanoma, primary retinitis pigmentosa etc.).