RESUMEN
Cell surface receptors and antigens present on Langerhans' cells (LC) suggest a close relationship between LC and interdigitating cells (IDC) in lymph node sections or lymphoid dendritic cells (LDC) in cell suspensions. One of the reported differences is that Fc receptors (FcR) which are present on LC, are absent on LDC. This difference can at least partly be explained by a laboratory artefact: FcR on murine LC are irreversibly modulated by the Ig that contaminates the bovine albumin commonly used for gradients. Furthermore, the demonstration of FcR on murine LC requires prolonged exposure to EA at 4 degrees C. A significant percentage of nonadherent, low density, Ig- lymph node cells also express such FcR. These cells can stimulate syngeneic mixed lymphocyte reactions as can LC isolated from epidermis. Consideration of LC as cutaneous representatives of the accessory cell system led to an investigation of their numbers in epidermal sheets of patients with acquired immunodeficiency syndrome (AIDS). A marked reduction in Ia+, ATPase+, OKT6+ LC was found as compared to controls, suggesting that accessory cell deficiency may play a role in the extreme immunodeficiency seen in AIDS patients.
Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/inmunología , Células Presentadoras de Antígenos/inmunología , Células de Langerhans/inmunología , Adenosina Trifosfatasas/metabolismo , Animales , Células Presentadoras de Antígenos/enzimología , Antígenos de Superficie , Antígenos de Histocompatibilidad Clase II , Humanos , Células de Langerhans/enzimología , Prueba de Cultivo Mixto de Linfocitos , Antígeno de Macrófago-1 , Macrófagos/inmunología , Ratones , Ratas , Receptores de Complemento , Receptores Fc , Receptores de IgG , Piel/inmunología , Linfocitos T Colaboradores-Inductores/inmunologíaRESUMEN
Both Langerhans cells from BALB/c mouse epidermis and nonadherent, low density (LD) cells, obtained from collagenase-treated minced lymph node, are stimulatory for isolated T cells in syngeneic mixed lymphocyte reaction (SMLR). The method of preparation of LD cells influences whether Fc receptor (FcR) can be detected on them. Fc receptors on nonadherent LD lymph node cells can be detected only if the same procedure is employed as that for Langerhans cell isolation, i.e., Ig-free bovine albumin must be used during gradient centrifugation and EA rosetting must be done overnight at 4 degrees C. Thus, both FcR+ and FcR- LD lymph node cells, as well as FcR+ Langerhans cells, stimulate SMLR. Although Ig+ cells in the LD fraction also stimulate the SMLR, their removal does not affect the stimulating capacity of the LD lymph node fraction.