0000000001001360
AUTHOR
Aino Laatikainen
Leukocyte chemotactic activity in cultures of unstimulated human lymphocytes.
We have shown earlier that unstimulated human lymphocytes in in vitro cultures produce migration inhibitory factor into the supernatant. The evidence of spontaneous lymphokine synthesis is strengthened further by this study, which demonstrates leukocyte chemotactic activity in these culture supernatants. The factor has a molecular weight of more than 5000 daltons, it resisted heating for 15 min at 100 degrees C, and showed maximum activity at dilution 1:4-1:8 of the supernatants.
Spontaneous lymphokine production by human B lymphocytes.
When human blood lymphocytes are cultured in vitro without any intended stimulus, they produce activities in the supernatant resembling lymphokine. This phenomenon was further investigated in the present study, where it has been demonstrated by physicochemical characterization and inhibition experiments that leukocyte migration inhibitory activity in the supernatants is due to leukocyte inhibitory factor (LIF). When T and B lymphocytes were purified by carbonyl iron and SRBC-rosette sedimentation, only B cells produced LIF and leukocyte chemotactic lymphokine(s) in subsequent cultures. B cells elaborated lymphokines without the help of T cells, the need for co-operation of monocytes was als…