Table 7.

Comparison of natural and functional characteristics of IVIg and HLA-I polyreactive mAbs.

Source, Nature, and Functions	Intravenous Immunoglobulin (IVIg)	HLA-I Polyreactive mAbs, TFL-006 & TFL-007
Manufacturer	Several pharmaceutical firms	Terasaki Foundation Laboratory, U.S. Patent No. 10,800.847;10/13/20
Source	Purified from pooled plasma of 10,000 blood donors	Immunized in mice with a heavy chain of HLA-ER107
Nature of antibody	Human, polyclonal IgG with trace levels of IgA	Murine purified monoclonal IgG
Subclass of IgG antibodies	IgG1, IgG2a, IgG3, IgG4	IgG2a
Purity	Contains soluble HLA antigens and other non-IgG proteins	100% purified protein of IgG2a [44,45]
	Cytokines, chemokines
Antibody reactivity	CCs & OCs of HLA-A, HLA-B, HLA-Cw, HLA-E, HLA-F	OCs but not CCs of HLA-A, HLA-B, HLA-Cw, HLA-E, HLA-F, HLA-G
	HLA-G, HLA-DR, HLA-DQA/DQB, HLA-DPA/DPB	None
	Fc receptors: FcgI, FcgII, FcgIII, FcgIV (tested) [96]	FcgII (anticipated)
	Blood groups: A, B, Rh	No
	Escherichia coli bacterial antigens ranging from	No
	antigens by different preparations of IVIg	No
	Human albumin	No
	Phospholipids	No
Binding site	Binds to both closed and open conformers	Binds only to open conformers
Stabilizer	Many, including sucrose in some preparations	None
Protein concentration	Highly variable, from 2 to 12%	Protein concentration adjusted to requirement
CD4+ T-cell suppression	PHA- or cytokine-activated T cells by apoptosis and necrosis	PHA-activated T cells
CD8+ T-cell proliferation	PHA-activated T-cells	PHA-activated T cells
B-cell proliferation	May induce differentiation	None
Anti-HLA antibody suppression	PRA antibody reduction	Suppress production of anti-HLA-I and anti-HLA-II IgG
	Suppress selected HLA-II antibody production
	Promote selected HLA-II antibody production
Expansion of Tregs	Yes	Yes
Special application	Not applicable	To monitor the presence of open conformers admixed with
		closed conformers on the bead sets. (e.g., LABScreen vs
		LIFECODE bead sets used in monitoring HLA antibodies