Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
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vắc-xin bại liệt uống, và một số loại vắc-xin adenovirus là những ví dụ của vắc-xin sống giảm độc lực virus. Virus vắc-xin bị giết chết (bất hoạt). Virus toàn bộ hoặc một số thành phần của virus, hoặc trong đó đã được ngừng hoạt động hóa học hoặc vật lý. | Vaccines and Immunotherapies 295 oral polio vaccine and some adenovirus vaccines are examples of attenuated live viral vaccines. Killed viral vaccines inactivated . Whole virus particles or some component of the virus either of which has been deactivated chemically or physically. These vaccines do not cause infection but stimulate an immune reaction. Usually repeated doses are required as one dose does not confer lifelong immunity. Large quantities of viral antigens per dose are necessary to produce an adequate response. Influenza Salk polio rabies and Japanese encephalitis vaccines are of this type. Recombinant antigens. Tend to be newer versions of earlier vaccines and furnish better protection with less risk and fewer side effects. Specific components that elicit production of protective antibodies are cloned. These express the gene that encodes that protein or protein complex. The new hepatitis B vaccine is this type. The different types of vaccines that produce immune responses in a variety of cell types are shown in Table 4.2. Vaccine-induced immunity is a relative science. Selecting the correct dosage s timing of dosages and determining the longterm efficacy are trials facing vaccine development. Normally B cells CD8 T cells and CD4 T cells mediate immune functions. B-cell functions may involve secretion of IgG antibodies or secretory IgA antibodies. CD4 and CD8 T cells provide support for B cells and CD8 T cells assist in killing human leukocyte antigen HLA -matched infected cells. B cells when mediated by T-helper cells are thought to provide long-lasting immunity despite negative antibody test results 2 . Table 4.2 Roles of Different Cell Types in Vaccine-Induced Immune System Development B-cells CD8 T cells CD4 T cells Live-attenuated virus vaccines inactivated virus vaccines protein antigens capsular polysaccharides with or without carrier. Live-attenuated virus vaccines. Live-attenuated virus vaccines inactivated virus vaccines protein antigens and .
