Polymorphonuclear neutrophils (PMNs) are capable of synthesizing various pro-inflammatory cytokines which may indirectly influence specific immune responses. PMNs may also have the capacity to present foreign peptides to helper T cells (Th cells). In support of this hypothesis, recent studies have shown that neutrophils, when activated by the correct combination of cytokines, can be induced to express cell surface major histocompatibility complex (MHC) Class II (DR) antigen, @entity7938 (B7.1) and @entity2937 (B7.2): molecules required for antigen presentation and subsequent T-cell activation. In this study we have used normal "resting" @entity1 peripheral blood neutrophils and demonstrated, using a mild fixation and permeabilization protocol, significant cytoplasmic "stores" of these molecules known to be important in antigen presentation. Cytoplasmic @entity11155 was found with two out of 20 normal donors tested whereas cytoplasmic @entity7938 and @entity2937 were found to a variable extent within all normal donors. Surprisingly, we also found several other neutrophil cytoplasmic CD antigens more commonly associated with B cells, i.e. @entity2225 , @entity10911 ( @entity10911 ) and @entity10317 ( @entity10317 ). All of these antigens were confined to the "resting" cell cytoplasm and were never found to be expressed on the cell surface. To exclude the possibility that these antigens were absorbed from plasma and to provide evidence for active synthesis, we used a novel whole blood in situ hybridization flow cytometry assay method to detect mRNA specific for these antigens within normal PMNs. We also conducted real-time polymerase chain reactions to confirm these findings using @entity10317 as a good example of an "inappropriately expressed" CD antigen. These observations therefore provide support for the hypothesis that @entity1 PMNs have the potential to express molecules required for antigen presentation and cell signalling.

Detection of cytoplasmic CD antigens within normal XXXX peripheral blood leucocytes.

@entity1 :: ('9606', 'Species') :: ['human'] @entity10911 :: ('1380', 'Gene') :: ['CD21', 'CR2/EBV-R'] @entity2937 :: ('942', 'Gene') :: ['CD86'] @entity7938 :: ('941', 'Gene') :: ['CD80'] @entity2225 :: ('54474', 'Gene') :: ['CD20'] @entity11155 :: ('3128', 'Gene') :: ['MHC Class II antigen'] @entity10317 :: ('933', 'Gene') :: ['CD22', 'BL-CAM']
@entity1 :: (9606,Species) :: ['human']
