| First Author | Guo WX | Year | 1997 |
| Journal | Int Immunol | Volume | 9 |
| Issue | 5 | Pages | 665-77 |
| PubMed ID | 9184912 | Mgi Jnum | J:98078 |
| Mgi Id | MGI:3577123 | Doi | 10.1093/intimm/9.5.665 |
| Citation | Guo WX, et al. (1997) Sequence changes at the V-D junction of the VH1 heavy chain of anti-phosphocholine antibodies alter binding to and protection against Streptococcus pneumoniae. Int Immunol 9(5):665-77 |
| abstractText | X-linked immune deficient (Xid) mice fail to produce anti-phosphocholine (PC) antibodies even after immunization with Streptococcus pneumoniae. Consequently, Xid mice are extremely susceptible to infection with S. pneumoniae, PC-specific B cells appear to undergo clonal deletion in Xid mice; however, a new thymus-dependent form of PC, 6-(O-phosphocholine)hydroxyhexanoate (EPC), can rescue PC-specific B cells from the bone marrow presumably by providing T cell help before clonal deletion. Analysis of PC-specific IgG hybridomas from Xid mice revealed utilization of several V-D junctional variants of the VH1 gene segment rearranged to different D and JH gene segments. The majority of Xid anti-PC antibodies exhibit an Asp-->Gly95H replacement at the V-D junction. These Gly95H VH1 variants associate with kappa 1C L chains to produce anti-PC antibodies that: (1) have low relative affinity for PC, (ii) are heteroclitic for nitrophenylphosphocholine and (iii) fall to bind to or provide protection against S. pneumoniae. Single prototypic V-D variants of the T15 idiotype (Asp95H), M603 idiotype (Asn95H) and M167 idiotype (Asp95H-Ala96H) were also induced in Xid mice. The M603-like and M167-like antibodies bound to and protected against S. pneumoniae even though they exhibited Kas for PC which were lower than T15 idiotype+ antibodies. These data demonstrate that small changes in the V-D junctional sequence of the T15 (VH1) heavy chain alter L chain usage and the structure of the PC binding site so that the PC expressed on S. pneumoniae is no longer recognized. |
