Studies on guinea pig skin cell cultures. V. Co-culture of pigmented melanocytes and albino keratinocytes, a model for the study of pigment transfer.

Mixed cultures of melanocytes (M) and keratinocytes (K) are easily obtained from pigmented guinea pig ear skin. They are suitable for the study of pigment transfer from M to K. However, quantitation is difficult because many K are already loaded with pigment prior to cultivation. A technique is presented in which pigment-producing M are co-cultured with K of albino origin. Pigmented guinea pig ear skin is split with trypsin and basal cells including M are harvested. The cell suspension is treated with sodium citrate which prevents the attachment of K (but not of M) to the culture substrate. Ninety per cent pure M cultures are obtained. Five to seven days later, another basal cell suspension is prepared, this time from albino ear skin. This second suspension is seeded on top of the pigment-forming culture of M. The number of contacts between albino K and pigment-forming M increases as a direct function of time. Contrarily, the number of K which become pigmented increases until the fifth day of co-culture and decreases thereafter.