       Document 0304
 DOCN  M9460304
 TI    Antigen targeting to antigen-presenting cells enhances presentation to
       class II-restricted T lymphocytes.
 DT    9404
 AU    Scardino A; Paroli M; De Petrillo G; Michel ML; Barnaba V; Fondazione
       Andrea Cesalpino, I Clinica Medica, Universita La; Sapienza, Rome,
       Italy.
 SO    Immunology. 1994 Jan;81(1):167-70. Unique Identifier : AIDSLINE
       MED/94178807
 AB    Receptor-mediated uptake increases by several orders of magnitude the
       efficiency of APC to internalize Ag, and is stringently required for the
       Ag-presenting function of T lymphocytes due to their inability to take
       up Ag non-specifically. We have previously reported that hepatitis B
       envelope antigen (HBenvAg) can be internalized by T cells via
       transferrin receptor (TfR). To evaluate if Ag targeting to receptors
       expressed on APC could be an effective tool for promoting Ag uptake and
       presentation, we tested the capacity of activated T cells not expressing
       TfR to induce HBenvAg-specific T-cell responses when pulsed with a
       hybrid particle containing HBenvAg coupled to gp120 of human
       immunodeficiency virus (HIV), exploiting the ability of gp120 to bind to
       CD4 receptor. We found that CD4+/TfR- T cells pulsed either with the
       hybrid particle or peptide (S193-207) but not with S, L Ag, a
       recombinant form of HBenvAg, induced a specific proliferative response
       of a T-cell clone recognizing peptide (S193-207) of HBenvAg. The finding
       that the addition of anti-CD4 monoclonal antibody (mAb) before the
       pulsing of CD4+/TfR- T cells with the hybrid particle drastically
       blocked the specific T-cell response, together with the finding that
       CD8+/TfR- T cells were unable to serve as APC even if pulsed with this
       molecule, demonstrated that CD4 receptor was crucial for the HBenvAg
       internalization. On the other hand, HBenvAg presentation by CD4+/TfR+ T
       cells pulsed with the hybrid particle was inhibited only when both
       anti-CD4 and anti-TfR were added before the pulsing. These results
       suggest that Ag targeting to APC receptors may be usefully exploited to
       improve Ag-presentation efficiency in potential immunotherapeutic
       approaches.
 DE    Antigen Presentation/IMMUNOLOGY  Antigen-Presenting Cells/*IMMUNOLOGY
       Antigens, CD8/ANALYSIS  Hepatitis B e Antigens/IMMUNOLOGY  Human  HLA-DR
       Antigens/*ANALYSIS  Receptors, Transferrin/*ANALYSIS  Support, Non-U.S.
       Gov't  T-Lymphocytes/*IMMUNOLOGY  T4 Lymphocytes/IMMUNOLOGY  JOURNAL
       ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

