Role of sulfatide-reactive vNKT cells in promoting lung Treg cells via dendritic cell modulation in asthma models.

Our previous studies have showed that sulfatide-reactive type II NKT (i.e. variant NKT, vNKT) cells inhibit the immunogenic maturation during the development of mature lung dendritic cells (LDCs), leading todeclined allergic airway inflammation in asthma. Nonetheless, the specific immunoregulatory roles of vNKT cells in LDC-mediated Th2 cell responses remain incompletely understood. Herein, we found that administration of sulfatide facilitated the generation of CD4+FoxP3+ regulatory T (Treg) cells in the lungs of wild-type mice, but not in CD1d-/- and Jα18-/- mice, after ovalbumin or house dust mite exposure. This finding implies that the enhancement of lung Treg cells by sulfatide requires vNKT cells, which dependent on invariant NKT (iNKT) cells. Furthermore, the CD4+FoxP3+ Treg cells induced by sulfatide-reactive vNKT cells were found to be associated with PD-L1 molecules expressed on LDCs, and this association was dependent on iNKT cells. Collectively, our findings suggest that in asthma-mimicking murine models, sulfatide-reactive vNKT cells facilitate the generation of lung Treg cells through inducing tolerogenic properties in LDCs, and this process is dependent on the presence of lung iNKT cells. These results may provide a potential therapeutic approach to treat allergic asthma.

Prolonged Remission Induced by FENofibrate in children with newly diagnosed type 1 diabetes (PRIFEN): protocol of a randomised controlled trial.

INTRODUCTION: Sphingolipids regulate proinsulin folding, insulin secretion and control beta cells apoptosis. Recent evidence has demonstrated that, among other factors, reduced amounts of sulfatide may be relevant in the development of type 1 diabetes (T1D). Thus, fenofibrate, which activates sulfatide biosynthesis, may prolong remission in subjects with T1D. The aim of the study is to evaluate clinical efficacy of fenofibrate on the maintenance of residual beta-cell function in children with newly diagnosed T1D. METHODS AND ANALYSIS: A total of 102 children aged 10-17 years with newly diagnosed T1D will be enrolled in a double-blind, two-centre randomised, non-commercial, placebo-controlled trial. Subjects who will meet all inclusion criteria will be randomly assigned to receive fenofibrate at a dose of 160 mg or an identically appearing placebo, orally, once daily, for 12 months. The primary endpoint will be the area under the curve of the C-peptide level during 2-hour responses to a mixed-meal tolerance test (MMTT). Secondary endpoints include fasting and maximum C-peptide concentration in the MMTT, parameters of diabetes control and glucose fluctuations, daily insulin requirement, inflammation markers, genetic analysis, safety and tolerance of the fenofibrate ETHICS AND DISSEMINATION: The study protocol was approved by the Bioethics Committee. The results of this study will be submitted to a peer-reviewed diabetic journal. Abstracts will be submitted to international and national conferences. TRIAL REGISTRATION NUMBER: EnduraCT 2020-003916-28.

Engineered arylsulfatase A with increased activity, stability and brain delivery for therapy of metachromatic leukodystrophy.

A deficiency of human arylsulfatase A (hASA) causes metachromatic leukodystrophy (MLD), a lysosomal storage disease characterized by sulfatide accumulation and central nervous system (CNS) demyelination. Efficacy of enzyme replacement therapy (ERT) is increased by genetic engineering of hASA to elevate its activity and transfer across the blood-brain barrier (BBB), respectively. To further improve the enzyme's bioavailability in the CNS, we mutated a cathepsin cleavage hot spot and obtained hASAs with substantially increased half-lives. We then combined the superstabilizing exchange E424A with the activity-promoting triple substitution M202V/T286L/R291N and the ApoEII-tag for BBB transfer in a trimodal modified neoenzyme called SuPerTurbo-ASA. Compared with wild-type hASA, half-life, activity, and M6P-independent uptake were increased more than 7-fold, about 3-fold, and more than 100-fold, respectively. ERT of an MLD-mouse model with immune tolerance to wild-type hASA did not induce antibody formation, indicating absence of novel epitopes. Compared with wild-type hASA, SuPerTurbo-ASA was 8- and 12-fold more efficient in diminishing sulfatide storage of brain and spinal cord. In both tissues, storage was reduced by ∼60%, roughly doubling clearance achieved with a 65-fold higher cumulative dose of wild-type hASA previously. Due to its enhanced therapeutic potential, SuPerTurbo-ASA might be a decisive advancement for ERT and gene therapy of MLD.

Inhibition of type I natural killer T cells by retinoids or following sulfatide-mediated activation of type II natural killer T cells attenuates alcoholic liver disease in mice.

UNLABELLED: Innate immune mechanisms leading to liver injury subsequent to chronic alcohol ingestion are poorly understood. Natural killer T (NKT) cells, enriched in the liver and comprised of at least two distinct subsets, type I and II, recognize different lipid antigens presented by CD1d molecules. We have investigated whether differential activation of NKT cell subsets orchestrates inflammatory events leading to alcoholic liver disease (ALD). We found that after chronic plus binge feeding of Lieber-DeCarli liquid diet in male C57BL/6 mice, type I, but not type II, NKT cells are activated, leading to recruitment of inflammatory Gr-1(high) CD11b(+) cells into the liver. A central finding is that liver injury after alcohol feeding is dependent upon type I NKT cells. Thus, liver injury is significantly inhibited in Jα18(-/-) mice deficient in type I NKT cells as well as after their inactivation by sulfatide-mediated activation of type II NKT cells. Furthermore, we have identified a novel pathway involving all-trans retinoic acid (ATRA) and its receptor (RARγ) signaling that inhibits type I NKT cells and, consequently, ALD. A semiquantitative polymerase chain reaction analysis of hepatic gene expression of some of the key proinflammatory molecules shared in human disease indicated that their up-regulation in ALD is dependent upon type I NKT cells. CONCLUSIONS: Type I, but not type II, NKT cells become activated after alcohol feeding. Type I NKT cell-induced inflammation and neutrophil recruitment results in liver tissue damage whereas type II NKT cells protect from injury in ALD. Inhibition of type I NKT cells by retinoids or by sulfatide prevents ALD. Given that the CD1d pathway is highly conserved between mice and humans, NKT cell subsets might be targeted for potential therapeutic intervention in ALD.

Enhanced antitumor efficacy and reduced systemic toxicity of sulfatide-containing nanoliposomal doxorubicin in a xenograft model of colorectal cancer.

Sulfatide is a glycosphingolipid known to interact with several extracellular matrix proteins, such as tenascin-C which is overexpressed in many types of cancer including that of the colon. In view of the limited success of chemotherapy in colorectal cancer and high toxicity of doxorubicin (DOX), a sulfatide-containing liposome (SCL) encapsulation approach was taken to overcome these barriers. This study assessed the in vitro cytotoxicity, biodistribution, therapeutic efficacy and systemic toxicity in vivo of sulfatide-containing liposomal doxorubicin (SCL-DOX) using human colonic adenocarcinoma HT-29 xenograft as the experimental model. In vitro, SCL-DOX was shown to be delivered into the nuclei and displayed prolonged retention compared with the free DOX. The use of this nanodrug delivery system to deliver DOX for treatment of tumor-bearing mice produced a much improved therapeutic efficacy in terms of tumor growth suppression and extended survival in contrast to the free drug. Furthermore, treatment of tumor-bearing mice with SCL-DOX resulted in a lower DOX uptake in the principal sites of toxicity of the free drug, namely the heart and skin, as well as reduced myelosuppression and diminished cardiotoxicity. Such natural lipid-guided nanodrug delivery systems may represent a new strategy for the development of effective anticancer chemotherapeutics targeting the tumor microenvironment for both primary tumor and micrometastases.

Evidence for extended age dependent maternal immunity in infected children: mother to child transmission of HIV infection and potential interventions including sulfatides of the human fetal adnexa and complementary or alternative medicines.

The two neighboring southwestern states of India, Karnataka and Maharashtra, have high incidence of HIV/AIDS and are among the six most high prevalence HIV infected states. In Karnataka state, the northern districts of Bagalkot, Belgaum and Bijapur (the three Bs) and in Maharashtra state, the southern districts of Sangli, Satara, and Solapur (the three Ss) are the areas with the highest incidence of HIV/AIDS. We have evaluated the incidence of maternal to child transmission (MTCT) of HIV-1 infection in Belgaum District which is more than 500 kilometers distance by road from the campus in greater Bangalore (Karnataka State). We have obtained the prenatal CD4 counts of HIV infected pregnant mothers. We have also screened the HIV infected children in two orphanages (rehabilitation centres for HIV infected children) in Belgaum District. The clinical conditions of these infected children were assessed for their CD4 counts, anti-retroviral therapy (ART) intake status, outpatient illnesses and body composition. We have observed that there is an influence of the age factor on the CD4 counts of the HIV infected children. Further, in view of the role of our recently found involvement of sulfatide, 3-O- galactosylceramide, in inhibition of HIV-1 replication and enhancement of hematopoiesis which is otherwise inhibited due to such infection, we have discussed the possible role of sulfatides that biologically occur in the fetal adnexa (placentatrophoblasts /amnion/chorion-umbilical cord), in containing HIV infection as a potential safer alternative to the ART regimens currently approved to be clinically practiced. Lastly, we have discussed the complementary and alternative medicine (CAM) therapies such as evidence based yoga and ayurveda as add-on to ART in potential elimination of MTCT of HIV infection. Out of a total of 150 children delivered by HIV infected mothers, 13 children were found to be positive as determined by the dried blood smear (DBS) for virological testing, giving an incidence of about 8.66% in the Belgaum district during the last two years, in spite of the prescription of currently available ART regimens. All the 13 HIV-transmitting mothers had normal vaginal deliveries. Though 12% of the total 150 deliveries required lower segment caesarean section (LSCS), none among them resulted in MTCT of HIV. Comparison of the prenatal CD4 counts between transmitting and non-transmitting mothers did not show significant differences (p=0.25) thus suggesting indirectly that HIV-1 proviral loads (undetermined / unavailable) need not necessarily determine the fate of incidence of vertical transmission. The mean age of 44 HIV infected children (14 females, 30 males) that were screened in two orphanages was 10.8±3.1 years. Out of these 44 children, 27 were taking ART (61.36%) with mean duration of consumption being 2.8±2.28 years. Fifty percent (n=22) of the children were suffering from at least one outpatient illness, out of which 13 were taking ART. Their mean basal metabolic rate (BMR), body mass index (BMI), muscle mass, fat mass and fat % were 795.45±106.9, 14.55±1.9 kg/m(2), 9.54±3.4 kg, 3.69±2.24 kg and 15.04±7.8% respectively. Comparison between the children taking ART (on-ART, n=27) and those not taking ART (non-ART, n= 17) showed that though there was no significant difference in the average age of the two groups, on-ART children had significantly higher BMR (p=0.05), and muscle mass (p=0.004), than non-ART. The CD4 counts, BMI, fat mass and fat percentage did not show significant statistical differences between the two groups. The CD4 counts of the children (both on-ART and non-ART) of age 8 years and below (n=12) were found to be significantly higher (p=0.04) than those of age 14 and above (n=10). All the children in age group of 14 years and above (n=10) except one child were on ART, whereas 7 out of 12 children in age group of 8 years and below were on-ART. In one of the rehabilitation centers called Aadhar, among non-ART children, a significant correlation was observed between the age of the child and CD4 counts (measured separately in the months of June 2011 and December 2011). Both the CD4 counts measured in June 2011 (n=6; r=-0.82, p= 0.04) as well as in December 2011 (n=6; r=-0.97, p=0.001) showed a significant decline as the age progressed. Also, at the same center, among on-ART children, the CD4 counts in June 2011 (n=7) and December 2011 (n=8) were significantly different between the children in the age group of 8 below years, and those in the age group of 14 years and above (p= 0.005). As HIV infected children grow in age, they may lose maternal derived immunity as shown by the decrease in CD4 counts, irrespective of their ART status. It is to be expected from these results that the conferred maternal immunity (possibly primarily humoral and secondarily cytotoxic immune responses) to the virus acquired at child birth taper off and eventually overcome by the generation of mutant HIV strains in the children, as the life spans of the infected children progress. We have discussed safer therapeutic interventions whose efficacy on HIV/AIDS may be synergistic to or even substitute the existing treatment strategies. Some of such interventions may even be customized to help eliminate MTCT. Further, these virus infected pregnant mother patient blood / serum samples could prove useful in the vaccine development against HIV infection.

Sulfatide--a new candidate for ART treatment in HIV-1 infection.

New combination drug treatment(s) now available to patients with HIV-1 infection allows them to live longer lives with good quality of life although they suffer from the incurable HIV-1 infection. In a previous study we found that sulfatide was efficient in lowering HIV-1 viral loads in SCID mice engrafted with human fetal liver/thymus tissues (SCID-hu). Current antiviral treatments carry an increased risk of other complications like cardiovascular disease and diabetes after long-term use. There is a need for new potent safe pharmaceutical agents. Endogenous sulfatide is a mixture of -isoforms, i.e. sulfatide molecules with different long-chain bases and fatty acid chain lengths and saturation. Sulfatide isoforms may have different physicochemical properties i.e, they are of different potency at different target cells. Other investigators have shown that incubation of cultured cells with sulfatide incorporated into the plasma membrane inhibited HIV-1 entry into the cells thereby inhibiting intracellular HIV-1 replication. We have shown that CD1d dependent stimulation by sulfatide may activate pDC antigen expressing cells that produce type I inteferons. Type I inteferons are known to reduce HIV-1 replication. This could provide a second likely explanation (after the inhibition of virus entry) for the more efficient lowering of HIV-1 viral loads in sulfatide versus AZT treated mice. This review aims to show the efficiency of sulfatide in reducing HIV-1 viral loads as compared to conventional HAART treatment. We also discuss the risks of HAART treatment and propose a clinical alternative of sulfatide in HIV-1 infection.

Role of sulfatide in vaccinia virus infection.

BACKGROUND INFORMATION: Vaccinia virus (VACV) was used as a surrogate of variola virus (genus Orthopoxvirus), the causative agent of smallpox, to study orthopoxvirus infection. VACV infects cells via attachment and fusion of the viral membrane with the host cell membrane. Glycosphingolipids, expressed in multiple organs, are major components of lipid rafts and have been associated with the infectious route of several pathogens. RESULTS: We demonstrate that the VACV-WR (VACV Western-Reserve strain) displays no binding to Cer (ceramide) or to Gal-Cer (galactosylceramide), but binds to a natural sulfated derivative of these molecules: the Sulf (sulfatide) 3' sulfogalactosylceramide. The interaction between Sulf and VACV-WR resulted in a time-dependent inhibition of virus infection. Virus cell attachment was the crucial step inhibited by Sulf. Electron microscopy showed that SUVs (small unilamellar vesicles) enriched in Sulf bound to VACV particles. Both the A27 and L5 viral membrane proteins were shown to interact with Sulf, indicating that they could be the major viral ligands for Sulf. Soluble Sulf was successful in preventing mortality, but not morbidity, in a lethal mouse model infection with VACV-WR. CONCLUSIONS: Together the results suggest that Sulf could play a role as an alternate receptor for VACV-WR and probably other Orthopoxviruses.

Sulfatide-mediated activation of type II natural killer T cells prevents hepatic ischemic reperfusion injury in mice.

BACKGROUND & AIMS: Hepatic ischemic reperfusion injury (IRI) is a major complication of liver transplantation and resectional hepatic surgeries. Natural killer T (NKT) cells predominate in liver, where they recognize lipid antigens bound to CD1d molecules. Type I NKT cells use a semi-invariant T-cell receptor and react with α-galactosylceramide; type II NKT cells use diverse T-cell receptors. Some type II NKT cells recognize the self-glycolipid sulfatide. It is not clear whether or how these distinct NKT cell subsets mediate hepatocellular damage after IRI. METHODS: We examined the roles of type I and type II NKT cells in mice with partial hepatic, warm ischemia, and reperfusion injury. RESULTS: Mice that lack type I NKT cells (Jα18-/-) were protected from hepatic IRI, indicated by reduced hepatocellular necrosis and serum levels of alanine aminotransferase. Sulfatide-mediated activation of type II NKT cells reduced interferon-γ secretion by type I NKT cells and prevented IRI. Protection from hepatic IRI by sulfatide-mediated inactivation of type I NKT cells was associated with significant reductions in hepatic recruitment of myeloid cell subsets, especially the CD11b(+)Gr-1(int), Gr-1(-), and NK cells. CONCLUSIONS: In mice, subsets of NKT cells have opposing roles in hepatic IRI: type I NKT cells promote injury whereas sulfatide-reactive type II NKT cells protect against injury. CD1d activation of NKT cells is conserved from mice to human beings, so strategies to modify these processes might be developed to treat patients with hepatic reperfusion injury.

Lipid compositions of human gastric fluid and epithelium: the role of sulfated lipids in gastric cytoprotection.

BACKGROUND: Gastric sulfatide, whose carbohydrate moiety resembles that of the anti-ulcer drug sucralfate, has been shown to play a role in mucosal protection in an experimental ulcer model. To elucidate the functional significance of gastric lipids, precise determination of the lipids in human gastric fluid and epithelium was performed, and the anti-ulcer effects of all lipids in the fluid were measured in mouse ulcer models. METHODS: The lipids in human gastric fluid and epithelium were analyzed by thin layer chromatography and immunostaining, and the anti-ulcer effects of gastric lipids were determined using mouse ulcer models. RESULTS: Human gastric epithelium contained both sulfatide and cholesterol sulfate (CS) as sulfolipids, which were also detected in gastric fluid, showing their stable natures in the gastric fluid. Hemorrhaging in HCl-induced gastric lesions was suppressed in a dose-dependent manner by the administration of sulfolipid-containing liposomes, but suppression of stress ulcers was only accomplished with CS-containing liposomes, ie, not with sulfatide-containing ones, due to the longer retainment of CS than sulfatide in the stomach. CONCLUSIONS: Among the lipids in human gastric fluid, CS was revealed to exhibit a gastroprotective activity, which was more effective than that of sulfatide.

Effects of a new synthetic selectin blocker in an acute rat thrombotic glomerulonephritis.

In an attempt to explore a novel therapeutic approach, a new synthetic sulfatide derivative (SKK60037) was evaluated in an acute rat model of P-selectin and leukocyte-dependent thrombotic glomerulonephritis (TG). In vitro, SKK60037 inhibits the function of P- and L-selectin more effectively than sialyl Lewis X (sLe(x)), a well-established selectin blocker. TG was induced by the intravenous administration of nephrotoxic globulin (NTG) to rats pretreated with a subclinical dose of lipopolysaccharide. In this model, platelet accumulation was remarkable within 10 minutes after induction of disease, followed by the infiltration of leukocytes, mainly neutrophils and macrophages. Thrombus formation and fibrinogen deposition in the glomeruli were observed within 1 hour, and they proceeded until 6 hours. P-selectin was highly expressed in glomeruli, whereas E-selectin and L-selectin ligands were not detected. We tested the effects of SKK60037 in this model in comparison with sLe(x) and antirat P-selectin monoclonal antibody (ARP2-4). SKK60037 blocked platelet accumulation in glomerular capillaries at 10 minutes after NTG injection. At 6 hours, leukocyte infiltration and thrombosis were significantly suppressed. Protective effects of SKK60037 were similar to those of ARP2-4, whereas sLe(x) showed minimum effect. The superior effects and more favorable characteristics of SKK60037 to sLe(x) suggest the potential of SKK60037 for clinical application.

Sulfatide and monoclonal antibodies prevent reperfusion injury in skin flaps.

Sulfatide binds to P- and L-selectin, which play important roles in the initiation of neutrophil-endothelial interactions. Sulfatide protects skin flaps from ischemia-reperfusion injury. The purpose of this study was to evaluate the augmented protection when anti-rat ICAM-1 and anti-rat LFA-1 antibodies are combined with sulfatide in the ischemia-reperfusion model of rat skin flaps. Sulfatide was administered intravenously just before elevation of the right abdominal epigastric flap, and monoclonal antibodies were injected 30 min before clamp release. The femoral artery and vein were clamped above and below the epigastric vessels for 11 h and then the clamp was released. The administration of both sulfatide and monoclonal antibodies significantly increased the flap surviving area (6.58 +/- 0.61 cm(2) versus the group with monoclonal antibodies alone, 4.43 +/- 0.32 cm(2), P = 0.01). In the untreated rats the area was 1.86 +/- 0.36 cm(2). Histological examination 24 h after reperfusion in the group treated with sulfatide and monoclonal antibodies showed only slight leukocyte invasion into the flap, and myeloperoxidase activity 24 h after reperfusion was significantly reduced. This study indicates that both sulfatide and monoclonal antibodies protect rat skin flaps from ischemia-reperfusion injury.

Transplantation tolerance by a combined therapy with sulfatide, anti-LFA-1/ICAM-1 monoclonal antibodies and FK506 in rat cardiac transplantation.

Selectins promote a rolling phenomenon of leukocytes along activated endothelial surfaces, which is the first step in the events that ultimately lead to leukocyte transmigration at acute inflammatory sites. Our previous study revealed that sulfatide, which is one of the selectin inhibitors, prolonged graft survival in rat cardiac allografts. In the present study, to obtain a longer graft acceptance, we examined a combination treatment of sulfatide, monoclonal antibodies (mAbs) against LFA-1/ICAM-1, and FK506 in a Fischer 344 (F344, RT1lvl) to Lewis (LEW, RT1l) rat heart transplantation. FK506 alone (n = 6) and FK506/sulfatide-treated LEW rats (n = 6) rejected F344 heart grafts with an MST of 49 and 55.2 days, respectively. Otherwise, four out of six heart grafts treated with sulfatide, mAbs against LFA-1/ICAM-1, and FK506 (n = 6) survived for over 100 days after transplantation. The proliferative response of alloreactive T cells obtained from tolerant rats against both F344 alloantigen and third-party alloantigen on day 104 postgrafting was significantly suppressed as compared to that from naive LEW rats. On light microscopic examination, specimens of tolerant rat on day 104 postgrafting showed an almost normal appearance. Our results suggested that blocking both each step of leukocyte entry and recognition of alloantigens by a combination treatment of sulfatide, mAbs against LFA-1/ICAM-1, and FK506 could lead to tolerance.

The role of P-selectin, sialyl Lewis X and sulfatide in myocardial ischemia and reperfusion injury.

The role of P-selectin and the ligands of selectins such as sialyl Lewis X and sulfatide was studied in a myocardial ischemia and reperfusion injury model. Anesthetized rabbits underwent the occlusion of coronary artery (30 min) followed by reperfusion (5 h). The inhibitory effect on myocardial ischemia and reperfusion injury was examined with infarct size normalized by area-at-risk. Intravenous administration of an anti-P-selectin monoclonal antibody, PB1.3 (2 mg/kg), reduced infarct size by 38%. Similarly, the administration of sialyl Lewis X-oligosaccharide (10 mg/kg) reduced infarct size by 53% significantly. Finally, the infarct size was significantly reduced bv 39% in sulfatide-treated group (10 mg/kg). These results suggest that P-selectin plays an important role in myocardial ischemia and reperfusion injury and that the ligands of selectins, such as sialyl Lewis X-oligosaccharide and sulfatide, have cardioprotective effect on myocardial ischemia and reperfusion injury.

Anti-inflammatory effects of sulfatides in selectin-dependent acute lung injury.

Selectins promote adhesive interactions between leukocytes and activated endothelial cells, the adhesion being mediated by 'counter-receptors' on endothelial cells and consisting of oligosaccharide conjugates containing sialic acid and fucose. There are also suggestions that selectins bind sulfated compounds, including sulfatides. Intravenous infusion of selectin-reactive oligosaccharides has been found to prevent selectin-dependent inflammatory lung injury. In the current studies using two models of neutrophil and selectin-dependent acute lung injury in rats, sulfatide and its modified versions were infused i.v. and the protective effects determined. Naturally occurring sulfatide, synthetic sulfatides and sulfated ganglioside were highly protective against lung injury following systemic activation of complement. Desulfated sulfatide was inactive. The protective effects of synthetic sulfatides required sulfation of galactose in position 3. Sulfatide was also protective in the IgG immune complex model of lung injury. The protective effects of sulfatides were associated with reduced content of myeloperoxidase (derived from neutrophils) in lung tissue. These data indicate that sulfatides have significant in vivo protective effects in neutrophil and selectin-dependent models of lung injury.

Effect of long-term treatment with sulfatide on hyperlipidemia and progression of atherosclerosis in WHHL rabbits.

Changes in serum lipids and lipoproteins and progression of atherosclerosis with age were examined in Watanabe heritable hyperlipidemic (WHHL) rabbits with or without treatment with sulfatide. The injection of sulfatide solution caused a reduction of serum triacylglycerols for five months including the period of treatment, but afterwards, failed to lower the level of total cholesterol, triacylglycerols and phospholipids, and to suppress the progression of atherosclerosis. Concentrations of LDL as a major serum lipoprotein in WHHL rabbits with or without the treatment with sulfatide were found to be about 64-fold those of normal rabbits by immunological assay using anti-LDL antiserum, whereas the contents of total cholesterol, triacylglycerols, and phospholipids in WHHL rabbit sera were found to be about 10-fold those of normal rabbits. All WHHL rabbits with or without the treatment with sulfatide contained very small amounts of HDL. Types of apoproteins of isolated LDL and VLDL fractions suggested that the former seemed to be derived from VLDL remnant, and the latter to be derived from chylomicron remnant. It was noted that all WHHL rabbit sera had a significant increased amount of lysophosphatidylcholine, and that the fatty acid composition of total serum lipids had almost no change except for slight decrease in arachidonic acid with age. Pathological examination showed that severe atherosclerotic lesions were not so different between WHHL rabbits with or without treatment with sulfatide at age over 22 months.

Regression of a transplanted guinea pig hepatoma after intralesional injection of an emulsified mixture of endotoxin and mycobacterial sulfolipid.

Mycobacterial sulfatides (sulfolipids) in admixture with endotoxin had tumor regressive activity comparable to trehalose-6,6'-dimycolate (TDM) and endotoxin in guinea pigs, but unlike TDM were neither toxic nor granulomagenic and had no antitumor activity in mice. The increased endotoxin lethality in mice pretreated with BCG was not observed in mice pretreated with sulfolipids or TDM instead of BCG.