Guinea pigs with cellular (delayed) hypersensitivity to the protein ferritin and to bacille calmette Guérin (BCG) vaccine were challenged intracorneally. Clinically and by light microscopy, the timing of the response and the character of the cellular infiltrate were similar in both instances. An electron microscopic study was made of the limbus and limbal cell population at varying times following challenge in the ferritin-sensitized animals. Quantitative analysis of the cell population at the limbus was made, and several features of the response have been emphasized. Characteristics of the reaction were: the presence of large numbers of histiocytes early in the reaction; intercellular edema and inflammation of the conjunctival epithelium; nodular aggregates of lymphoid cells; and the small number of "activated" lymphoid elements present. These findings were discussed and related to known mechanisms of cellular hypersensitivity.
Howes EL. Cellular Hypersensitivity in the CorneaAn Analysis of the Limbus and Limbal Cellular Infiltration by Light and Electron Microscopy. Arch Ophthalmol. 1970;83(4):475-488. doi:10.1001/archopht.1970.00990030475017