To Study the change regularity of special antibody in cases of severe acute respiratory syndrome

By studying the change of the special antibodies titer IgG, IgM and nucleocaspid to SARS corona virus in family clustering cases , searching and testing the special antibody to SARS corona virus in the patients kinfolks. Testing special antibody titer to SARS corona virus of 14 patients from 5 different families and their 10 kinfolks continuously by IFA and antigen -capturing ELISA methods, taken samples in the 7~(th), 14~(th), 30~(th), 60~(th(, 120~(th), 180~(th), 210~(th),270~(th( ,360lhday after SARS patients infected by SARS corona virus, dilute them, and then measure titers of three kinds of antibodies. During the testing of IgG antibody titer of the 14 SARS patients by IFA method, in the 120111 day, the average titer is up the highest value, it is 1/1 120; in the 180th day, the average titer begins to descend, it is 1/262. in the 360th day, the average titer is 1/71. During the testing of IgM titer, the average titer is 1/32, it is obviously lower than it in IgG testing; the IgM titer of the most SARS patients are disappear after 120 days. The average value of nucleocaspid antibody titer is lower than it in IgG antibody. But there are some differences in 5 cases. While IgG antibody titer begins to descend in the 180th day, nucleocaspid antibody titer begins to ascend obviously, it is up to 1/790. 210~(th) day begins to descend. In the meantime, we have tested special antibody to SARS corona virus of their 10 kinfolks (include 2 children) who have contacted with SARS patients closely. The samples are taken in the 14~(th) , 30~(th) , 60~(th) day, and all the special IgG, IgM and nucleocaspid antibody to SARS corona virus are negative. By testing the special IgG antibody to SARS corona virus of the 14 family clustering cases ,we find the special IgG antibody titer of the SARS patient is higher, and it can remain for a long time. As for the nucleocaspid antibody titer of some SARS patients ascend obviously after 18Odays, we think that it provide useful information for vaccine development and it is necessary for us to study more in the clinic. There is no special blood serum antibody to SARS corona virus in their 10 kinfolks of the SARS patients.