CHOM . . . Wu Xueling's team selected the broad-spectrum neutralizing antibodies converted into IgG and IgA using the HIV surface membrane proteins shown by VSV.

Commissioning editor's disease is the infection of human cells through the surface protein.the transmembrane protein on the surface of the virus is a glycosylated protein of trimer, which has a lot of conformation and changes continuously during the process of virus infection.in the past, free proteins were used to label antigen-specific B cells when sorting broad-spectrum neutralizing antibodies against HIV. Then, the original viral transmembrane protein trimer can only be purified in the form of monomer or solidified trimer after losing the support of cell membrane. These purified free proteins are unlikely to completely remodel the original transmembrane proteins on the virus surface Constitutive image.in order to overcome this deficiency, on April 20, 2020, the research group of Wu Xueling from the Aaron Diamond AIDS research center of Columbia University was in the cell host & amp; The article VSV displayed HIV-1 envelope identities broadly neutralising antibacterials class switched to IgG and IgA was published in the journal microbe Virus (vesicular stomatitis virus) was used as a platform to display the membrane proteins on the surface of HIV and to label antigen-specific B cells. Five broad-spectrum neutralizing antibodies against HIV were isolated from the blood samples of two patients (Code: M4008 and m1214). Three of them showed 30-65% coverage rate and good action intensity, which reflected to a large extent The overall neutralizing antibody activity in the plasma of patients showed that the HIV surface protein displayed by VSV was successful as a B cell marker.in order to further analyze the B-cell lineages of these three broad-spectrum neutralizing antibodies, the research group conducted high-throughput sequencing of B-cell receptor (BCR) of these two patients.comparing the sequencing results with the three broad-spectrum neutralizing IgG antibody sequences, we not only found the same clonogenic variant in the same type of IgG, but also found two antibodies, M4008_ N1 and m1214_ N1, we also found the same clonogenic variant of IgA! What an unexpected discovery! So far, the previously isolated anti HIV neutralizing antibodies are IgG type, and this is the first time that IGA type anti HIV broad-spectrum neutralizing antibody is found, and it is a unique conversion into IgG and IgA broad-spectrum neutralizing antibody! As we all know, and as the textbook teaches, antibody type conversion is from the initial IgM type B cells to IgG or IgA type B cells.although it has been found that IgG is further converted into IgA in vitro B cell culture or BCR high-throughput sequencing, this phenomenon has never been described in human antibodies with known functions.this phenomenon has been confirmed and clarified in two patients' two anti HIV broad-spectrum neutralizing antibodies for the first time, which is of great significance and is a beneficial supplement to the current immunology textbooks! Finally, the team analyzed the epitope recognition of the two broad-spectrum neutralizing antibodies on the surface protein of the virus, and found that both of them recognized new epitope.M4008_ N1 recognizes the top of V3 with strong immunogenicity. However, the antibody used to recognize this epitope could not effectively neutralize HIV, so M4008 can not effectively neutralize HIV_ The way and angle of N1 identifying this epitope must be unique.the second antibody m1214_ N1 recognizes a new, narrow epitope from V2 to V5, so it is named "v2v5 corridor epitope".the binding site of the antibody is analyzed and described by the structure obtained by freeze electron microscopy, so it is very clear and clear.the definitions of these new epitopes also provide new targets for the design of HIV vaccines.the findings of this article are fascinating.first of all, the team used VSV as a platform to display the surface protein of HIV, and used it to mark the success of B cells, and overcome a technical problem of sorting out the broad spectrum neutralizing antibody of HIV.secondly, the research group unexpectedly found that the two types of broad-spectrum neutralizing antibodies have been converted to IgG and IgA, and through the extremely unusual mechanism of further conversion from IgG to IgA.finally, the virus epitopes recognized by these two neutralizing antibodies are new.so the question is, does the recognition of these new epitopes determine the fate of these two antibodies from IgG to IgA, or is the recognition of new epitopes just a coincidence? How common is the further conversion of IgG to IgA? Does it occur only in people with chronic HIV infection or during acute HIV infection? Will other viral infections novel coronavirus infections, including the current global pandemic, cause IgG to further convert to IgA? These questions will be left to the future antibody research to find the answer Original link: plate maker: kisauce