Effect of exchange transfusion with Fluosol DA 20% on splenic distribution and immunocompetence of rat lymphocytes

Enhancement of the Arthus reaction and suppression of delayed type hypersensitivity (DTH) by pluronic F-68, a detergent frequently used to prepare perfluorocarbon emulsions

The effect of a 20% w/v RM101 (perfluorobutyltetrahydrofuran) emulsion containing 5% w/v of the detergent Pluronic F-68 or 5% w/v Pluronic F-68 given alone on the Arthus reaction and on delayed type hypersensitivity (DTH) were evaluated in female A/J mice. The test substances were administered i.v. at 1% body weight at 0,4,7,14 and 28 days prior to the i.p. immunization with 10(7) sheep red blood cells (SRBC). The increase in footpad swelling at 4 h (Arthus reaction) and at 24 h (DTH) after elicitation with the s.c. administration of 10(8) SRBC into the left footpad was used to assess immune competence. Pluronic F-68 given alone enhanced the Arthus reaction only when administered on day 0 of immunization. Pluronic F-68 given alone, as well as the perfluorocarbon emulsion containing Pluronic F-68, suppressed the 24 h DTH for as long as 4 days prior to immunization. Nonemulsified perfluorocarbon, on the other hand, had no effect on either the Arthus reaction or on DTH. The immunostimulatory agent, levamisole, administered (10 mg/kg i.p.) 1.5-2 h prior to immunization with SRBC counteracted both the Arthus reaction and the DTH response produced by Pluronic F-68. The present data clearly demonstrate that the changes in Arthus reaction and the DTH response are due to the Pluronic F-68 used to emulsify the RM101 perfluorocarbon; the changes induced by the detergent in these two immune parameters probably involve separate mechanisms.

Lymphoid tissue responses to emulsified perfluorochemicals: comparative aspects

The effects of a single, low dose (10 ml/kg) injection of the perfluorochemical (PFC) emulsion, Fluosol-DA 20%, on lymphoid tissues and antibody production against sheep red blood cells (SRBC) have been studied relative to the timing of immunization in rats and mice. Intravenous (i.v.) or intraperitoneal (i.p.) injection of emulsion in both species produced alterations in lymphoid tissue weights and the magnitude of these responses was highly tissue- and species-specific. Injection of Fluosol-DA tended to potentiate the humoral immune response to SRBC but this depended on timing and route of emulsion administration relative to immunization. We conclude that lymphoid tissue responses to emulsified PFCs are highly variable and depend upon a number of factors including: emulsion composition and dose; route and timing of administration relative to immunological "challenge"; tissue and species examined.

Lymphoid tissue responses to perfluorocarbon emulsion in rats: time course effects relative to immune challenge

1. The effects of either intraperitoneal (i.p.) or intravenous (i.v.) injection of low doses (10 ml/kg) of the commercial emulsion, Fluosol-DA 20% (F-DA), on lymphoid tissues and antibody production against sheep red blood cells (SRBC) have been studied relative to the timing of immunization in rats. 2. Spleen and liver weights were significantly increased in response to injection of F-DA although no consistent pattern was observed. 3. Thymus weight was decreased following F-DA injection in some experimental groups whereas mesenteric lymph node (MLN) weights were unchanged throughout. 4. The mean plasma antibody titre to SRBC was significantly increased in some groups of animals injected with F-DA both before or after immunization; maximum titres were observed following injection of emulsion simultaneously with SRBC. 5. These results show that lymphoid tissue weights and plasma antibody titres in rats immunized with SRBC vary according to the timing and route of a previous or subsequent injection of F-DA.

Emulsified perfluorochemicals for oxygen-transport to tissues: effects on lymphoid system and immunological competence

Data from both in vivo and in vitro studies to assess lymphoid tissue and immune system responses to emulsified PFCs and their components have been discussed. It may be concluded that the extent to which PFC emulsions are retained in lymphoid tissues and their effects on the manifestation of humoral immune responses to immunological "challenges" is variable and depends upon: (1) Emulsion composition; (2) Dose administered; (3) Route of administration; (4) Tissue examined; (5) Timing of emulsion administration relative to immune challenge; and (6) Species studied. Such variability in the responses to emulsified PFCs has inevitably introduced difficulties in assessing their effects upon immunological competence. Further work is needed determine the extent to which lymphoid tissue functions may be altered by PFC emulsions and identify the active component(s) and mechanism(s) involved.

Effect of Fluosol DA 20% on antibody response to type 3 pneumococcal polysaccharide in rats

Exchange transfusion with the oxygen-carrying resuscitation fluid, Fluosol DA 20% (FDA), interferes with the efficacy of penicillin therapy of pneumococcal infection in rats. Because this effect could not be attributed to an interaction between FDA and penicillin, the effect of FDA on the ability of rats to mount an antibody response to type 3 pneumococcal polysaccharide was tested. FDA (25 ml) was administered by isovolumetric exchange transfusion. Rats were immunized intravenously with 0.2 microgram of type 3 pneumococcal polysaccharide 3 days before, 1 day before, 1 day after, or 3 days after transfusion with FDA. IgM and IgG antibody responses were determined by ELISA 0, 3, 7, 10, 14, 21, and 28 days after immunization. When rats were immunized 3 days before or 1 day before transfusion with FDA, antibody levels were increased above control levels and remained relatively high through Day 28. When the animals were immunized 1 day after transfusion, antibody levels were approximately the same as in the control group. When the rats were immunized 3 days after transfusion, antibody levels were suppressed. These data suggest that FDA does not inhibit the humoral immune response when administered after or within 1 day before immunization, but does inhibit the response when immunization is given 3 days after transfusion.

Lymphoid tissue responses to perfluorocarbon emulsion in mice

The effects of either intraperitoneal or intravenous injection of low doses (5 or 10 ml/kg) of the proprietary emulsified perfluorocarbon-based blood substitute, Fluosol-DA 20%, on mouse lymphoid tissue and antibody production against sheep erythrocytes (SRBC) have been investigated. Mean liver weight was significantly increased and gut mesenteric lymph node (MLN) weights decreased in all animals injected with Fluosol-DA, irrespective of route of administration. In contrast, spleen weight decreased following intravenous injection of emulsion at 5 ml/kg. The mean plasma haemagglutination response to SRBC was significantly (P less than 0.01) increased in animals injected intraperitoneally with Fluosol at both doses but was similar to control in all other cases. These results show that lymphoid tissue responses to Fluosol-DA in mice are variable and that antibody production against intraperitoneally-injected SRBC is enhanced by prior injection of emulsion into the peritoneal cavity.

Perfluorocarbons as oxygen-transport fluids

1. An overview of the proposed biological applications of perfluorocarbons and their emulsions as oxygen-transport fluids is presented. 2. Aspects of the properties, preparation, composition and physiological assessment of perfluorocarbon emulsions are discussed. 3. The experimental basis for some of the potential therapeutic uses of PFCs in liquid ventilation, treatment of decompression sickness, organ perfusion, oxygenation of ischaemic and malignant tissues, and as contrast media for NMR imaging is described. 4. The extent to which emulsified perfluorocarbons may have value as substitutes for red blood cells is discussed in detail. Data from both animal and human studies with such emulsions is reviewed. Brief consideration is also given to the possible use of native and modified haemoglobin in blood replacement together with recent work on the preparation of so-called "synthetic red cells".