Abstract: The purpose of the present invention is to elucidate a relationship between deregulation of signaling by CD22 and a rapid response of B cells by IgG-BCR and the like, and to provide a method capable of inducing a rapid immune response and defending against infection instead of vaccine. The present invention relates to a method for promoting an immune response causing such a strong proliferation of clones and production of a large amount of antibody-producing cells as those seen in the memory immune response even in the naive B cells expressing IgM-BCR and IgD-BCR by inhibiting the CD22 function in B cells; and to a method for screening a substance capable of promoting the immune response based on a change in the CD22 function in B cells.

Abstract: The purpose of the present invention is to elucidate a relationship between deregulation of signaling by CD22 and a rapid response of B cells by IgG-BCR and the like, and to provide a method capable of inducing a rapid immune response and defending against infection instead of vaccine. The present invention relates to a method for promoting an immune response causing such a strong proliferation of clones and production of a large amount of antibody-producing cells as those seen in the memory immune response even in the naive B cells expressing IgM-BCR and IgD-BCR by inhibiting the CD22 function in B cells; and to a method for screening a substance capable of promoting the immune response based on a change in the CD22 function in B cells.

Abstract: An SiO.sub.2 insulating layer is formed on an Si substrate, and an Si.sub.3 N.sub.4 insulating layer is formed on the SiO.sub.2 layer. A notch is formed in the Si.sub.3 N.sub.4 layer using a resist film as a mask. The SiO.sub.2 layer is etched using the Si.sub.3 N.sub.4 layer as a mask, thereby forming an opening larger than the notch cut in the SiO.sub.2 layer. As a result, the Si.sub.3 N.sub.4 layer extends over the opening in an overhanging manner. When As.sup.+ ions are implanted in the periphery of the notch of the Si.sub.3 N.sub.4 layer, the ion-implanted portion of the Si.sub.3 N.sub.4 layer is arcuated toward the base region. When a metal such as Ti is deposited on the arcuated portion, the metal is also deposited on the arcuated portion and the portion of the emitter region matching with the notch, thereby forming an emitter electrode portion.