MHC Class I–Restricted CTL Responses to Exogenous Antigens

Abstract

reactivity in F1 (A ϫ B) hosts. Although the mode of transfer of antigenic material from the transplanted, im-and Jo ¨rg Reimann † munogenic cells to host-derived APC during cross-prim-*Microbiology and Tumor Biology Center ing has not been elucidated, recent evidence for the Karolinska Institute shedding of antigenic vesicles (Zhou et al., 1992a; Ra-S-171 77 Stockholm poso et al., 1996) and for the release of immunogenic, Sweden apoptotic blebs (Casciola-Rosen et al., 1996) provides † Institute of Medical Microbiology interesting possibilities for antigen transfer to APC. Hu-University of Ulm ang et al. (1996b) recently studied cross-priming using D-89069 Ulm influenza virus nucleoprotein-transfected H-2 d tumor Federal Republic of Germany cells given to irradiated H-2 dxb mice rescued with bone marrow from TAP Ϫ/Ϫ H-2 b mice. These mice developed a normal T cell compartment (on the TAP ϩ/ϩ thymic epi-References processing compartment and thus efficiently capture those few MHC-I molecules that have escaped from the

Alternative processing for MHC class I presentation by immature and CpG‐activated dendritic cells

“…A special compartment for processing of extracellular antigen for MHC class I expression in antigen-presenting cells, mostly phagocytic cells, was described to be endolysosomal [6][7][8][9]. The presence of internalized antigen together with MHC class I and class II molecules in a compartment similar to the classical low pH MHC class II processing compartment (MIIC) was demonstrated [25].…”

“…The presence of internalized antigen together with MHC class I and class II molecules in a compartment similar to the classical low pH MHC class II processing compartment (MIIC) was demonstrated [25]. MHC class I molecules can enter this compartment either via the ER or through recycling from the cell surface and can then bind processed peptides through peptide exchange [7,9]. Many different cell types express an alternative MHC class I processing pathway, but there is comparatively little information regarding DC.…”

“…where this could occur have been suggested: transfer from uptake vesicles into the cytosol followed by the classical MHC class I pathway [5] and processing and peptide loading of MHC class I in endolysosomes or phagosomes [6][7][8][9][10]. The endolysosomal compartment can obtain MHC class I molecules either directly from the ER or by recycling from the cell surface [9,11] and can export, by regurgitation, antigenic material for the direct binding to MHC class I expressed on the cell surface [12].…”

“…The endolysosomal compartment can obtain MHC class I molecules either directly from the ER or by recycling from the cell surface [9,11] and can export, by regurgitation, antigenic material for the direct binding to MHC class I expressed on the cell surface [12]. The leakage pathway is unique to DC, whereas the endolysosomal pathway has been mostly described for other cells, including B cells, macrophages and neutrophils [5-9, 11, 12] but was also recently reported for DC [10,13,14].…”

A convenient cancer vaccine therapy with in vivo transfer of interleukin 12 expression plasmid using gene gun technology after priming with irradiated carcinoma cells

“…Through this mechanism, class I-restricted CD8 + CTL is activated by corresponding exogenous ( foreign ) antigens. 18,19 This type of antigen -presentation pathway is called an alternative MHC class I pathway. DCs play the important role as APCs in cross -priming, 20 and cross -priming of CTL requires CD4 + T cells.…”