Localization of antigen on lymph node dendritic cells after exposure to the contact sensitizer fluorescein isothiocyanate. Functional and morphological studies.

Abstract

We have examined the cells involved in the development of contact sensitivity to FITC in CBA mice. After skin painting with antigen, the number of dendritic cells (DC) in the draining lymph nodes increased by 30 min, was maximal at 48 h, and returned to normal by 6 d. Derivation of some DC from Langerhans' cells of the skin was indicated from the presence of Birbeck granules observed in some DC isolated 24 h after skin painting. The DC acquired FITC and by 8 h there were two populations, one highly fluorescent and the other less fluorescent. The highly fluorescent cells were present between 8 h and 3 d after sensitization, and during this period the DC were potent at initiating primary proliferative responses of normal syngeneic T lymphocytes in vitro. Between days 3 and 5 the numbers of lymphocytes in the draining lymph node increased. During this period purified T lymphocytes did not express detectable levels of antigen, but enriched B cell populations expressed antigen transiently on day 1, 2, or 3 after exposure to antigen. The results showed that, during a 3-d period after exposure to antigen, DC expressed antigen and stimulated T cell proliferation. We speculate that low amounts of FITC binding selectively to veiled cells or lymph node DC in the first hours after exposure to antigen are not immunogenic but that Langerhans' cells acquire high levels of antigen, enter the nodes, and initiate immune responses.

Superiority of the ear pinna over muscle tissue as site for DNA vaccination

“…injection, the response is likely distributed over several lymph nodes. 31 The mechanical irritation by needle injection may induce local cytokine secretion and activate and recruit additional APC.…”

Src homology 2 domain‐containing protein tyrosine phosphatase substrate 1 regulates the induction of Langerhans cell maturation

“…When LC encounter exogenous antigens, including haptens and microorganisms, they capture and process them to generate MHC/peptide complexes on their surface. LC migrate from the epidermis to draining lymphoid tissues in order to initiate naive T cells and to present the MHC/peptide complexes to T cells with the necessary adhesion molecules and costimulatory signals [1][2][3][4][5][6][7]. During this migration, LC mature from a dormant into an activated functional state and down-regulate their endocytotic activity.…”

Calcium channel blockers suppress the contact hypersensitivity reaction (CHR) by inhibiting antigen transport and presentation by epidermal Langerhans cells in mice

“…In CHR, LC first take up antigens by phagocytosis or pynocytosis [7], then they migrate from the epidermis into the regional lymph nodes [22,29]. Our investigation demonstrated that CCB inhibited the capacity of LC to take up and transport antigens to the regional lymph nodes.…”

“…After painting of FITC on the skin as hapten, FITC-labelled dendritic cells appeared in the draining lymph nodes [22]. Therefore, we analysed by flow cytometry whether or not CCB affect the ability of LC to take up and transport FITC from the footpads to the popliteal lymph nodes.…”