Human CD152 (CTLA-4) is a cell surface glycoprotein expressed at low levels on activated T cells (1). CD152 is a high affinity receptor for the costimulatory molecules CD80 (B7-1) and CD86 (B7-2) and appears to function as a negative regulator of T cell activation (2, 3). A soluble fusion protein combining the extracellular (125aa) domain of human CD152 and murine IgG2a Fc (CTLA-4 Ig) was developed (4).
Molecular Structure: A soluble 110 kd dimeric fusion protein consisting of the extracellular (125aa) domain of human CTLA-4 fused to murine IgG2a Fc (233aa), with a predicted non glycosylated monomeric molecular weight of 40.1 kd.
Sequence:
CD152 mature EC: mhvaqpavvlassrgiasfvceyaspgkatevrvtvlrqadsqvtevcaatymtgneltflddsictgtssgnqvnltiqglramdtglyickvelmypppyylgigngtqiyvidpepcpdsdf
+linker: gt
fused to murine IgG2a Fc (233aa): eprgptikpcppckcpapnllggpsvfifppkikdvlmislspivtcvvvdvseddpdvqiswfvnnvevhtaqtqthredynstlrvvsalpiqhqdwmsgkefkckvnnkdlpapiertiskpkgsvrapqvyvlpppeeemtkkqvtltcmvtdfmpediyvewtnngktelnykntepvldsdgsyfmysklrvekknwvernsyscsvvheglhnhhttksfsrtpgk
Transfectant Cell Line: BHK
Functional Application: CD152 Ig binds with high affinity to human or mouse CD80 (B7-1) and CD86 (B7-2) (4, 5). CD152-muIg blocks the binding of anti-human CD80 (B7-1) and anti-humanCD86 (B7-2) mAbs to recepters on Raji cells. It cross reacts with CD80 and CD86 accross a broad range of mammalian species including pig (6, 7).
References:
1. T. Lindsten, et al, (1993) J Immunol 151: 3489-3499.
2. T.L. Walunas, et al, (1994) Immunity 1: 405-413.
3. N.J. Karandikar, et al, (1996) J Exp Med 184: 783-788.
4. A.H. Cross, et al, (1995) J Clin Invest 95: 2783-2789.
5. P.A. Morton, et al, (1996) J Immunol 156: 1047-1054.
6). Takamatsu H, RME Parkhouse, et al. (1999) Immunology 97(2):211-213.
7). Le Leduec JB, B Dubois, et al. (2016) Vaccine 34(7): 914-22. PMID: 26768129
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所以一个细菌或病毒可以有很多的抗原。
若已进入细胞内。则先由巨噬细胞吞噬降解。并形成抗原-MHC复合体传送到表面。被辅助性T淋巴细胞识别和效应T淋巴细胞识别后。效应T淋巴细胞被激活。分解靶细胞。然后再由效应B细胞分泌的抗体进一步消灭病毒。
还有不清楚的么？
荚膜（capsule）是某些细菌在生长繁殖过程中分泌的一层黏液性物质，包围在细胞壁外，通常这种黏液层厚度小于0.2μm，成分是多糖或多肽，只有在营养丰富时或在动物体内，细菌才产生这种半抗原性质的黏液性物质。它具有保护菌体免受巨噬细胞等的捕捉和吞噬，因而具有抗吞噬抗消化、侵袭力强、与致病性关系密切等特点。像肺炎球菌、炭疽杆菌等都有这类荚膜。有些细菌的荚膜层较薄，小于0.2μm，称为微荚。
像链球菌的M蛋白、伤寒杆菌的Vi抗原、大肠杆菌的K抗原等都属于这类微荚膜。
请赐教！
