Kindly provided by TJ Turner-Stokes and K Woollard, Imperial College, London, U
Markers and Staining Protocols Rat Monocytes
His48 originally was described as a granulocyte marker some 30 years ago but the molecule recognized has apparently not been identified. It has been used as a second reciprocal marker for rat monocyte subsets, since it gives a strong signal in CD43low cells (Barnett-Vanes et al, PLoS ONE 11:e0142520, 2016). This combination is now being used widely (e.g. Turner-Stokes et al, JASN, 31:2523, 2020, Keshvari et al, PLoS Genet 17:e1009605, 2021, Kiefer et al, Front. Immunol. 12:641224, 2021, Irvine et al, J Leuk Biol. 107:221, 2020). Of note, CD4 is also differentially expressed with higher levels on the CD43high monocyte subset (Yrlid et al, J Immunol, 176: 4155, 2006, Barnett-Vanes et al, PLoS ONE 11:e0142520, 2016) and this marker also has potential for dissection of the two subsets. ED1 (CD68) also has been used to identify monocytes with subset definition via CD43 (Grad et al, Drug Deliv Transl Res., 8:945, 2018)
More recently blood monocytes were identified using rats with a GFP transgene under the control of the CD68 promotor. Here the GFP high monocytes were stained for CD43 and His48 (Turner-Stokes et al, JASN, 31:2523, 2020). However, most studies use wildtype blood cells, where they use different positive and negative markers to identify monocytes and then subsets are defined via CD43 and His48. Here non-classical monocytes are GFPposCD43hiHIS48int and classical monocytes are GFPposCD43loHIS48hi.