Virus Inactivation in Hemoglobin Solutions by Heat

Abstract

To determine the feasibility of heat treating hemoglobin solutions to inactivate viruses, we performed experiments on the thermal stability of this protein and found that the structure and function of deoxyhemoglobin are well preserved during incubation at 60 degrees C for 10 hours at a pH of 7.5. Model viruses and the human immunodeficiency virus were rapidly inactivated under these conditions. The results imply that incubation at 60 degrees C is a practical method for inactivating viruses in hemoglobin solutions.

Focal Cerebral Ischemia in Rats: Effect of Hemodilution with α-α Cross-Linked Hemoglobin on Brain Injury and Edema

“…Viral contamination was eliminated and protein purification achieved by heat pasteurization. 26 - 27 The DCLHb was diluted to a concentration of = 10 gdL ' by adding electrolyte and buffer solution (Table 1 for lot release analysis). The solution was kept frozen (-70° C) until needed for the current study when it was thawed to 5° C, and on the day of the study passively warmed to room temperature and diluted to 7 gdL" 1 with lactated ringers to achieve the oncotic pressure of whole blood.…”

Diaspirin cross-linked hemoglobin improves neurological outcome following reversible but not irreversible CNS ischemia in rabbits.

“…Cell-free hemoglobin was obtained from outdated human blood, cross-linked, 33 and rendered virus free by heat treatment. 36 - 37 The DCLHb used in these studies was electrolyte balanced and had the following properties: pH 7.36 at 37°C, oncotic pressure of approximately 42 to 44 mm Hg (hyperoncotic with plasma), oxygen affinity of 32 mm Hg at 37°C and pH 7.4, and a viscosity of <1.5 centistokes at 37°C. Controls received electrolyte-balanced and oncotically matched human serum albumin (HSA).…”

&alpha;&alpha;&ndash;Crosslinked Hemoglobin: Was Failure Predicted by Preclinical Testing?

“…The constraints caused by the intersubunit crosslinking are expressed as a 5–fold higher rate for the unliganded R to T allosteric transition. Interestingly, these detailed studies were not repeated for the heat–treated protein, even though subtle alterations in the O 2 equilibrium curves were reported by Baxter [42]. …”

“…To test the immunogenicity of DCLHb, Estep et al [42]administered repeated doses to rhesus monkeys and could not demonstrate DCLHb–specific IgG or IgM antibodies, either by direct measurements or by intradermal skin tests. The same group screened 29 normal human donors and could find no evidence of preexisting anti–DCLHb.…”

“…The reaction mixture was heated to 60°C for 10 h at pH 7.5, and the less stable unreacted tetramers precipitated out of solution. Although several methods of virus removal and inactivation were evaluated by Baxter [41], this increased stability was exploited to introduce a heat viral inactivation step [42, 43, 44, 45]. The final product was formulated in either Ringer’s acetate, Ringer’s lactate or other physiologic buffer solutions for biological testing.…”