Serial sections from the human HG (HG1). From A to K, sections are reacted with Ab NCL-MHCn (anti-MHCneonatal), Ab F1.652 (anti-MHCembryonic), Ab NCL-MHCd (anti-MHCembryonic), Ab S46 (anti-MHCslow tonic), Ab N2.261, (anti-MHCII, -MHCI, -MHCeom, -MHCαcardiac), Ab SC-71 (anti-MHCIIa), Ab 2F7 (anti-MHCIIa), Ab 4A6 (anti-MHCextraocular), Ab A4.74 (anti-MHCIIA>MHCIIX), Ab MY-32 (anti-MHCII) and Ab A4.84 (anti-MHCI). Note absence of reaction with Abs to uncommon MHCembryonic, MHCextraocular, MHCneonatal and MHCslow tonic. Also note reaction of Ab N2.261 reacts with all HG fibers and of Abs SC-71 and 2F7 with a subset of MHCII (Ab MY-32+/Ab NCL-MHCn-) fibers. Symbols identify the same muscle fibers in serial sections. + = fiber with profile MHCI-IIX, ˙ = MHCI-IIX, * = MHCIIA, ^ = MHCI-IIA, ° = MHCI. Sections A, C, D and H also reacted with anti-laminin Ab D-18. Calibration bar = 50μm.