Instillation of Allogeneic Lung Antigen-Presenting Cells Deficient in Expression of Major Histocompatibility Complex Class I or II Antigens Have Differential Effects on Local Cellular and Humoral Immunity and on Pathology in Recipient Murine Lungs

This study was designed to investigate whether follicular dendritic cells (FDC) can activate B cells to a state in which they can function as effective antigen-presenting cells (APC). High buoyant density (i.e., resting) B cells specific for 2,4-dinitro-fluorobenzene (DNP) were incubated with DNP-ovalbumin (OVA) bearing FDC, after which their capacity to process and present to an OVA-specific T cell clone was assessed. The efficacies of alternative sources of antigen and activation signals in the induction of B cell APC function were compared with those provided by FDC. Only FDC and Sepharose beads coated with anti-immunoglobulin (Ig)kappa monoclonal antibody provided the necessary stimulus. FDC carrying inappropriate antigens also induced B cell APC function in the presence of exogenous DNP-OVA. However, in circumstances where soluble DNP-OVA was limiting, FDC bearing complexes containing DNP, which could crosslink B cell Ig receptors, induced the most potent APC function. Analysis by flow cytometry revealed that within 24 h of coculture with FDC, a significant percentage of B cells increased in size and expressed higher levels of major histocompatibility complex class II. By 48 h, an upregulation of the costimulatory molecule, B7/BB1, occurred, but only when exposed to the FDC bearing DNP. Taken together, the results demonstrate that FDC have the capacity to activate resting B cells to a state in which they can function as APC for T cells. The stimuli that FDC provide may include: (a) an antigen-dependent signal that influences the upregulation of B7/BB1; and (b) possibly a signal independent of crosslinking mIg that results in Ig internalization. The relevance of these findings to the formation of germinal centers and maintenance of the humoral response is discussed.

Download Full-text

A mouse aminopeptidase N is a marker for antigen-presenting cells and appears to be co-expressed with major histocompatibility complex class II molecules

European Journal of Immunology ◽

10.1002/eji.1830230946 ◽

1993 ◽

Vol 23 (9) ◽

pp. 2358-2364 ◽

Cited By ~ 39

Author(s):

Anette Stryhn Hansen ◽

Ove Norén ◽

Hans Sjöström ◽

Ole Werdelin

Keyword(s):

Major Histocompatibility Complex ◽

Major Histocompatibility Complex Class ◽

Antigen Presenting Cells ◽

Class Ii ◽

Aminopeptidase N ◽

Complex Class ◽

Major Histocompatibility ◽

Histocompatibility Complex ◽

Antigen Presenting

Download Full-text

Exogenous antigens gain access to the major histocompatibility complex class I processing pathway in B cells by receptor-mediated uptake.

Journal of Experimental Medicine ◽

10.1084/jem.184.3.1179 ◽

1996 ◽

Vol 184 (3) ◽

pp. 1179-1184 ◽

Cited By ~ 70

Author(s):

Y Ke ◽

J A Kapp

Keyword(s):

Dendritic Cells ◽

Major Histocompatibility Complex ◽

B Cells ◽

Major Histocompatibility Complex Class ◽

Class I ◽

Complex Class ◽

Receptor Mediated Endocytosis ◽

Histocompatibility Complex ◽

Antigen Presenting ◽

Gain Access

Professional antigen-presenting cells, such as macrophages, dendritic cells, or B cells, take up soluble, exogenous antigens (Ags) and process them through the class II pathway. Several reports have shown that phagocytic macrophages also process particulate or soluble forms of exogenous Ag via the class I pathway. By contrast, B cells normally do not process soluble, exogenous Ag by way of the class I pathway unless Ags are directly introduced into the cytoplasm. Here we report that B cells present exogenous Ag via the class I pathway when Ags are taken up by receptor-mediated endocytosis. Thus, specialized methods of Ag uptake such as phagocytosis or receptor-mediated endocytosis deliver exogenous Ag into the class I pathway of Ag processing and presentation.

Download Full-text