Edgar S. Cathcart

Improvement of in vitro mitogen proliferative responses in non-Hodgkin's lymphoma patients exposed to fractionated total body irradiation.

Patients with non‐Hodgkins lymphomas who failed to respond to chemotherapy were treated with low dose fractionated total body irradiation (TBI). Prior to, during and after scheduled therapy, their clinical status was evaluated and peripheral blood studies were performed to enumerate EAC and E rosetting cells and to measure proliferative responses to mitogens. Peripheral blood abnormalities were present prior to TBI using these in vitro assays. Patients who obtained clinical remissions following therapy had restoration of mitogen proliferative responses, whereas patients who showed no response or progressive disease had no change in their ability to proliferate in response to mitogens. Normalization of EAC and E rosetting profiles often occurred regardless of clinical response. These data indicate that low dose fractionated TBI produces clinical and in nitro detectable immunological changes. Furthermore, they show that improvement in mitogen responsiveness correlates best with good clinical responses.

The acute phase response in Syrian hamsters elevates apolipoprotein serum amyloid A (apoSAA) and disrupts lipoprotein metabolism

Lipoprotein metabolism was assessed in hamsters following subcutaneous injection of AgNO3. Apolipoprotein serum amyloid A (apoSAA) peaked at 36 h, followed by elevations in plasma cholesterol at 56 h and triglycerides at 96 h. There was a striking increase in LDL and a de-crease in HDL. Migration of all acute phase (AP) lipoproteins was retarded compared to controls and SDS-PAGE electrophoretic analysis was consistent with agarose gel profiles that revealed increased apoB-rich VLDL, IDL and LDL and decreased apoAl-rich HDL2 fractions. Cholesterol transported by LDL of AgNO3 treated hamsters was double that of controls while the pool of HDL-cholesterol was only two-thirds that of controls. Fasting triglyceride and cholesterol secretion rates were depressed sharply at 24 h. After E. coli lipopolysaccharide (LPS) injection, apoSAA-HDL particles bound avidly to cultured peritoneal macrophages (mos) but in vitro exposure of tissue mos to LPS did not alter the binding characteristics of either control-or apoSAA...

Antioxidants in Experimental Amyloidosis of Young and Old Mice

Santoguin and vitamin E were added to the diets of six week old CBA/J mice that were fed mouse chow and received daily subcutaneous casein (CAS) injections and 24 month old C57BL/6Nia mice fed a casein enriched diet respectively. DNA synthetic responses to Phytohemagglutinin (PHA) and Concanavalin A (ConA) were measured in spleen cell cultures to determine the effects of these potent antioxidants on cellular immune function. The incidence and degree of amyloidosis was measured after Congo red staining of formalin fixed sections.

A unique amyloidogenic apolipoprotein serum amyloid A (apoSAA) isoform expressed by the amyloid resistant CE/J mouse strain exhibits higher affinity for macrophages than apoSAA1 and apoSAA2 expressed by amyloid susceptible CBA/J mice

CBA/J and other inbred strains of mice that express the amyloidogenic apolipoprotein serum amyloid A (apoSAA) apoSAA2, together with apoSAA1, are susceptible to amyloid A (AA) amyloidosis, whereas CE/J mice that express a single unique isoform, apoSAACEJ, are resistant. Studies indicate that CBA/JxCE/J hybrid mice that express apoSAA2 in the presence of apoSAACEJ are protected from amyloidogenesis. To define a mechanism by which expression of apoSAACEJ may protect from AA formation in the presence of apoSAA2, binding of recombinant apoSAA (r-apoSAA) isoforms, validated by N-terminal sequencing, to a murine macrophage cell line was investigated. Maximal specific binding occurred after incubation of radiolabeled apoSAA with IC-21 macrophages (1x105 cells/ml) for 30 min at 4 degreesC. The binding of 125I-r-apoSAA1, 125I-r-apoSAA2 and 125I-r-apoSAACEJ was specific and saturable, with an affinity (Kd) of about 2.8, 3.2 and 1.3 nM, respectively, and approximately 2-4x106 sites per cell. Competitive binding experiments indicate apoSAACEJ binds with higher affinity to macrophages than does either apoSAA1 or apoSAA2. We suggest that greater cellular affinity of apoSAACEJ compared to apoSAA2 may contribute to protection from AA amyloid in certain CBA/JxCE/J hybrid mice by interfering with interaction of apoSAA2 by macrophages and hence either membrane associated or intracellular degradation.

Degradation of Serum Amyloid A in Amyloid‐Susceptible and Amyloid‐Resistant Mouse Strains

Degradation of serum amyloid A (apoSAA) by resident peritoneal cells (RPCS) and conditioned medium (CDM), prepared with RPCS, from amyloid‐susceptible CBA/J mice, amyloid‐resistant CE/J mice and their amyloid‐resistant CBA/J × CE/J F1 progeny was investigated in vitro. Serum amyloid A was derived from murine acute phase (AP) plasma and associated with high density lipoprotein (HDL). Degradation of apoSAA by RPCS and CDM from CBA/J mice was complete while degradation by RPCS and CDM from CE/J mice did not occur. Degradation of apoSAA by RPCS and CDM from CBA/J × CE/J F1 hybrid mice was indistinguishable from that by RPCS and CDM from the CBA/J parent. Intermediate fragments were not detected with either RPCS or CDM from CBA/J mice or CBA/J × CE/J F1 hybrid mice. Degradation of apoSAA was inhibited by phenylmethanylsulfonyl fluoride (PMSF) indicating that the enzyme, secreted into the fluid phase, was a serine esterase. Unlike apoSAA, HDL‐associated apoA‐1 remained intact. It was thus concluded that while selective degradation of HDL‐associated apoSAA (apoSAA‐HDL) by RPCS from the CBA/J and CE/J mice was significantly different, the genetic study did not support the hypothesis that there was direct linkage between impaired degradation of apoSAA‐HDL in the CE/J mouse strain and protection against amyloid fibril formation. As amyloid resistance in CBA/J × CE/J F1 hybrid mice is not attributable to failure to express the amyloidogenic isoform apoSAA2, the study supports the original hypothesis that amyloid resistance may be linked to expression of apoSAAcej

Diet, amyloid enhancing factor (AEF) and amyloidogenesis: an hypothesis.

At least two forms of amyloidosis, amyloid A (AA) and prion protein (PrP), can be transmitted by dietary ingestion of an agent(s) present in crude mammalian tissues. Although the incubation time for PrP or scrapie-induced diseases to develop in experimental animals extends over months or years, AA or secondary amyloidosis in mice is inducible within a week. In response to inflammatory stimuli we hypothesize that dietary factor(s) modulate the rate at which beta-pleated sheet fibrils accumulate in most forms of amyloidosis. The critical importance of precursor protein polymorphism, cell surface proteoglycans (PG), lipids and apolipoprotein metabolism has also been addressed in this hypothesis.

Dietary n-3 fatty acids and arthritis

Abstract. We have evidence that dietary fish oil (FO) decreases severity of collagen‐induced arthritis (CIA), changes the fatty acid composition of macrophage (Mϕ) membrane phospholipids, decreases Mϕ synthesis of prostaglandins (PGs), changes chemotactic ability of Mϕs, and affects metabolism of acute phase proteins. Gender also has pronounced effects on susceptibility to CIA and Mϕ prostaglandin profiles. The mechanisms by which dietary n‐3 fatty acids may act to alleviate symptoms of CIA, as well as interactions of dietary n‐3 and n‐6 fatty acids and gender are discussed. We suggest that the ability of FO diets to influence favourably the course of chronic inflammatory diseases is mediated via alterations in n‐6 fatty acid metabolism and that intrinsic differences in n‐6 fatty acid metabolism may account not only for our reported gender differences in incidence and severity of CIA, but also the well‐documented sexual dimorphism in immune/inflammatory responses in general.

Clinical applications of T, B, and K cell determinations in rheumatic diseases: A review*

NE OF THE MAJOR QUESTIONS in modern immunology is how thymusderived (T) cells and bone marrow-derived (B) cells interact to achieve mutual cooperation and negative feedback control. 1 It is becoming clear that disturbances in the intricate balance between T and B cells may result in a variety of clinical disorders, especially those considered to be autoimmune syndromes. 2 This development is largely due to the fact that in experimental animal models and in the clinical presentation of these disorders, several immunologic abnormalities leading to tissue injury have been well documented and shown to be a prerequisite for the manifestation of the disease state. This review will briefly summarize the abnormal interactions between T and B cells and the way in which their derangement may lead to autoimmunity. Special attention will be placed on the enumeration of peripheral blood lymphocytes by membrane-associated cell markers and the possible pathogenetic, diagnostic, and prognostic significance of these findings. DEFINITIONS AND NOMENCLATURE For the purpose of this review, T cells will be defined as thymus-derived lymphocytes capable of initiating delayed hypersensitivity and allograft reactions, elaborating lymphokines, and participating in the defense of the host against in

Macrophage function in azocasein-induced amyloidosis in CBA/J and A/J mice

It is known that a single gene governs resistance to amyloidosis induced by azocasein in A/J compared to CBA/ Jmice. We wished to determine whether this trait might be linked to differences in macrophage activation as measured by Feγ-receptor (Fcγ-R) and C3h receptor (C3b-R) phagocytosis of sheep erythrocytes and/or TNF secretion by adherent resident peritoneal cells. Macrophages from preamyloidotic and amyloidotic CBA/J mice showed marked enhancement of Feγ-R and C3h-R binding activity. Macrophages from A/Jmice receiving multiple azocasein injections showed a significant increase in Fcγ-R but not in C3b-Rphagocytic indices. Adherent peritoneal cells from control and azocasein-treated A/J Write produced higher TNF levels than control and azocasein-treated CBA/J mice. In both strains, peritoneal macrophage TNF secretion was depressed after 10 azocasein injections. Our findings differ from previous studies in which the amyloid deposition phase was associated with normal or depressed phagocytosis. On the oth...

Dietary modulation of apolipoprotein serum amyloid A (apoSAA) metabolism and prevention of amyloidosis in aging C57BL/6J and SJL/J mice

Abstract The specific effect of acute inflammation on apoSAA and lipoprotein metabolism was determined in two strains of mice that are prone to develop spontaneous age-associated systemic amyloidosis. C57BL 6J and SJL J mice were maintained on purified diets, relatively rich in fat and differing only with respect to protein constituents, i.e., casein (20%) versus soy protein (20%). After 18 months, aging mice of either strain and on either diet were injected subcutaneously with AgNO3 thus inducing a powerful acute phase response as evidenced by increases in plasma LDL and apoSAA-rich HDL. None of the mice in each of the dietary groups developed amyloidosis. Cholesterol levels were elevated during the acute phase response in both mouse strains, although the hypercholesterolemia was less pronounced in C57BL 6J mice and in SJL J mice fed soy protein compared with casein. Control plasma triglyceride levels were lower in C57BL 6J mice in both dietary groups compared to the SJL J strain. By contrast, C57BL 6J mice fed either protein increased the triglyceride concentration, whereas in SJL J mice, triglyceride levels were not altered by casein but were decreased significantly by soy protein diets. Oir findings show for the first time that dietary protein intake modulates the acute phase response in rodents. Furthermore, the data support the concept that alterations in lipid metabolism during the acute phase response may represent a protective mechanism whereby HDL-cholesterol and phospholipids are directed to sites of inflammation for connective tissue repair.