1         11        21        31        41        51        61        71        81        91        101       111       121       131       141       151       161       171       181       191       201       211       221  
                       |---------|---------|---------|---------|---------|---------|---------|---------|---------|---------|---------|---------|---------|---------|---------|---------|---------|---------|---------|---------|---------|---------|----
 CD28_BOVIN            -MLR-LLLALNFFPSIQVAENKILVKQSPMLVVNDNEVNLSCKYTYNLFSKEFRASLYKGADSAVEVCAVNGNHSHPLQS-TNKEFNCTVKVGNETVTFYLQDLYVNQTDIYFCKLEVLYPPPYIDNEKSNGTIIHVKEKHLCPSPRSPESSKPFWALVVVNGVLVFYSLLVTVALSNCWMKNKRNRMLQSDYMNMTPRRPGPTR-RHYQPYAPARDFAAYRS  
 CD28_HUMAN            -MLR-LLLALNLFPSIQVTGNKILVKQSPMLVAYDNAVNLSCKYSYNLFSREFRASLHKGLDSAVEVCVVYGNYSQQLQVYSKTGFNCDGKLGNESVTFYLQNLYVNQTDIYFCKIEVMYPPPYLDNEKSNGTIIHVKGKHLCPSPLFPGPSKPFWVLVVVGGVLACYSLLVTVAFIIFWVRSKRSRLLHSDYMNMTPRRPGPTR-KHYQPYAPPRDFAAYRS  
 CD28_RAT              MTLRLLFLALSFF-SVQVTENKILVKQSPLLVVDNNEVSLSCRYSYNLLAKEFRASLYKGVNSDVEVCVGNGNFTYQPQFRPNVGFNCDGNFDNETVTFRLWNLDVNHTDIYFCKIEVMYPPPYLDNEKSNGTIIHIKEKHLCHAQTSP---KLFWPLVVVAGVLLCYGLLVTVTLCIIWTNSRRNRLLQSDYMNMTPRRLGPTR-KHYQPYAPARDFAAYRP  
 Q9BDM8                -MLR-LLLALNLLPSIQVTGNKILVKQSPMLVAYDNAVNLSCKYSYNLFSREFRASLHKGLDSAVEVCVVYGNYSQQLQVYSKTGFNCDGKLGNESVTFYLQNLYVNQTDIYFCKIEVMYPPPYLDNEKSNGTIIHVKGKHLCPSPLFPGPSKPFWALVVVGGVLACYSLLVTVAFCIFWMRSKRSRLLHSDYMNMTPRRPGPTR-KHYQPYAPPRDSAAYRS  
 CD28_CHICK            -MLG-ILVVLCLIPAADVTENKILVAQRPLLIVANRTATLVCNYTYNGTGKEFRASLHKGTDSAVEVCFISWNMT-KINSNSNKEFNCRGIHDKDKVIFNLWNMSASQTDIYFCKIEAMYPPPYVYNEKSNGTVIHVRETPIQTQE--PESATSYWVMVAVTGLLGFYSMLITAVFIIYRQKSKRNRYRQSDYMNMTPRHPPHQKNKGYPSYAPTRDYTAYRSWQ  
 CD28_MOUSE            MTLRLLFLALNFF-SVQVTENKILVKQSPLLVVDSNEVSLSCRYSYNLLAKEFRASLYKGVNSDVEVCVGNGNFTYQPQFRSNAEFNCDGDFDNETVTFRLWNLHVNHTDIYFCKIEFMYPPPYLDNERSNGTIIHIKEKHLCHTQSSP---KLFWALVVVAGVLFCYGLLVTVALCVIWTNSRRNRLLQVTTMNMTPRRPGLTR-KPYQPYAPARDFAAYRP  
 Q9BDN2                -MLR-LLLVLNLFPSIQATGIKILVKQSPMLEAYDNTVNLTCKYSCNLFSRQFQASLHKGVDSAVEVCAVHGNYSQLLQVHSATGFNCDGKLGNESVTSYLQNLYVNQTDIYFCKIEIMYPPPYLDSEKSNGTIIHVKGKHLCPGPSFSGPSQPFWALAVVGGVLASYSLLVTVALSVFWMRSRRSRLLHSDYMNMTPRCPGPTR-RHYQPYAPPRDFAAYRS