Immunotherapy of coccidioidomycosis

Diagnosis, Treatment, and Outcome of Coccidioidal Osseous Infections: A Systematic Review

Extrapulmonary infections by Coccidioides spp., though rare, can occur via dissemination, affecting singular or multiple sites, including the skin and musculoskeletal system. Skeletal involvement often manifests as osteomyelitis, particularly in the axial skeleton. The present systematic review evaluates all documented cases of skeletal coccidioidomycosis to assess the diagnostic and treatment strategies alongside the outcomes, drawing insights from an analysis of 163 verified cases. A systematic review following PRISMA guidelines identified all studies reporting skeletal infections by Coccidioides spp. up to 2023 from the PubMed and Scopus databases. Eligible studies evaluated osteoarticular infections from Coccidioides spp. Data extraction included demographics, microbiological data, diagnostic methods, and treatment outcomes. Of the 501 initially identified records, a total of 163 patients from 69 studies met the inclusion criteria. Most cases were from the USA, predominantly males, while the median age of the population was 36 years. Diabetes mellitus was the common comorbidity (14.7%). C. immitis was the most prevalent pathogen. The spine and hand were common sites of infection (17.5% and 15.1%, respectively). Osteomyelitis by Coccidioides spp. was diagnosed, in most cases, by positive cultures (n = 68; 41.7%), while, in 49 (30.9%), both the histological examination and cultures yielded the fungus. Surgical debridement was performed in 80.9% of cases. A total of 118 (72.3%) patients were treated with monotherapy, while combination therapy with two or more antifungal agents was reported in 45 (17.7%). Amphotericin B (either liposomal or deoxycholate) was the most commonly given agent as monotherapy in 51 (31.2%) patients, while 30 (18.4%) patients received itraconazole as monotherapy. The rate of infection's resolution was higher in patients undergoing surgical debridement (79.5%), compared to those treated only with antifungal agents (51.6%, p = 0.003). Treatment outcomes showed complete resolution in 74.2% of patients, with a mortality rate of 9.2%. Coccidioidal osseous infections present diagnostic and therapeutic challenges. Surgical intervention is often necessary, complementing antifungal therapy. Vigilance for Coccidioides spp. infections, especially in regions with endemicity, is crucial, particularly when bacterial cultures yield negative results.

Transfer Factor: Myths and Facts

Transfer factor (TF), also called "Lawrence transfer factor", or dialyzable leukocyte extract (DLE), has been used since the mid-twentieth century to transfer specific skin hypersensitivity through the injection of leukocytes from immunized donors to animals and humans. The main mechanism of action of TF has been suggested at the level of cell-mediated immunity, as it induces the production of migration inhibitory factor (MIF) and interferon gamma (IFN-γ). Otherwise, TF can inhibit nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB), and decrease tumoral necrosis factor α (TNF-α) and IL-4 levels. Given these biological effects, TF has been prescribed for a wide variety of conditions including infections, allergies, autoimmunity, and cancer, with inconsistent results. The exact nature of TF, however, remains unknown, so it has been impossible to accurately define its pharmacokinetics or dosage. This is further complicated because researchers have used TF in a variety of ways across the different studies: antigen-specific or non-antigen-specific, orally or subcutaneously administered, human and non-human origin. In this review we summarize the most important data about what TF is, its mechanism of action, how it is produced, its biological effects, and the available clinical trials using it, in order to establish its role and potential clinical applications in modern medicine.

Profiles of cytokine production in recipients of transfer factors

Transfer factors (TF) are proteins that transfer the ability to express cell-mediated immunity from immune donors to non-immune recipients. The mechanisms of these effects have not been defined. The experiments described in this report were undertaken to test the hypothesis that a mechanism through which the beneficial effects of TF are expressed in clinical situation is through "education" of the immune system to produce certain cytokines in response to antigenic stimulation. BALB/c mice were sensitized to Herpes simplexvirus (HSV) either by sublethal systemic or cutaneous infections by administration of a HSV-specific TF. One week later their spleen cells were collected and single cell suspensions were stimulated in vitro with irradiated HSV or concanavalin. A Culture supernatants were collected and assayed for content of IL-2, IL-4, IL-10 and IFN-g. Spleen cells from infected mice responded to concanavalin A and to HSV by secreting large amounts of IL-2 and IFN-g, modest amounts of IL-10, and no IL-4. Transfer factor recipients produced similar cytokine profiles in response to concavalin A. These mice, however, responded to HSV by secreting IFN-g, but no IL-2. Thus, TF treatment selectively affects cytokine production in response to antigenic stimulation.

Structural nature and functions of transfer factors

Transfer factors are molecules that "educate" recipients to express cell-mediated immunity. This effect is antigen-specific. The most consistent effects of transfer factors on the immune system are expression of delayed-type hypersensitivity and production of lymphokines such as macrophage migration inhibitory factor (MIF), which is probably identical to gamma-interferon in response to exposure to antigen. Transfer factors bind to antigens in an immunologically specific manner. This discovery has enabled us to isolate individual transfer factors from mixtures that contain several transfer factors. This reactivity probably explains the specificity of individual transfer factors, and it has provided a method for purification of individual transfer factors to apparent homogeneity. The purified materials are immunologically active and antigen-specific. They have molecular weights of approximately 5,000 Da and appear to be composed entirely of amino acids. Transfer factors appear to offer a novel means of molecular immunotherapy for certain patients with defective cell-mediated immunity.

Immune response in mice infected with Candida albicans in the mycelial form

The effect of the infection with the mycelial form of a Candida albicans strain (Mycology Dept.) upon the immune system in mice was studied. BALB/c mice were infected intraperitoneally in a single dose of a 3 x 10(6), 6 x 10(6) and 12 x 10(6) cell suspension of the strain. Macrophages's activity was studied the days 7, 14, 21, 28, 35, and 42 after inoculation, by the following assays: phagocytosis in vitro, mononucleated phagocytic system by the colloidal carbon clearance technique, the lymphocyte's activity by the direct plaque forming cells technique (PFC) and delayed hypersensitivity (DTH). Infection with the mycelial form did not affect the peritoneal macrophage's phagocytic ability, neither modified the delayed hypersensitivity to sheep red blood cells (SRBC). However, a slight and transient depression of the lymphocyte stimulation was found. Suppression of PFC to SRBC was high when a 12 x 10(6) cell suspension was used in contrast to the infection with blastospores. These results suggest that systemic infection by Candida albicans in its mycelial form do not induce a non specific immunosuppression.

Immunoregulation in experimental murine candidiasis: specific suppression induced by Candida albicans cell wall glycoprotein

Immune regulation in candidiasis is inferred from studies of both human and animal infection, with a suppressive role suggested for cell wall polysaccharide. To study the immunosuppressive potential of Candida albicans in a murine model, whole blastoconidia or purified cell wall components of C. albicans were tested for their effects on the development of acquired immune responses by superimposing a pretreatment regimen upon an established immunization protocol. CBA/J or BALB/cByJ mice were pretreated twice intravenously with 100 micrograms of mannan (MAN), 100 or 200 micrograms of glycoprotein (GP), or 5 X 10(7) heat-killed C. albicans blastoconidia, followed 1 week later by an immunization protocol of two cutaneous inoculations of viable C. albicans blastoconidia given 2 weeks apart. Delayed hypersensitivity (DTH) to GP or to a membrane-derived antigen, B-HEX, was tested 7 days after the second inoculation, and lymphocyte stimulation was tested with mitogens and Candida antigens after 12 days. To assess protection, mice were challenged intravenously with viable C. albicans blastoconidia 14 days after the second cutaneous inoculation and sacrificed 28 days later for quantitative culture of kidneys and brains. Sera were obtained for enzyme-linked immunosorbent assays at selected intervals. Pretreatment with GP resulted in specific in vivo suppression of DTH to GP but not to B-HEX antigen and specific in vitro suppression of lymphocyte stimulation to GP but not to other Candida antigens or mitogens. MAN and heat-killed C. albicans blastoconidia had no such effects. GP pretreatment also diminished the protective effect of immunization against challenge, demonstrable in the brain, while not altering significantly the production of antibody in response to infection. Contrary to clinical evidence, MAN was not immunosuppressive in this model, and in fact, the immunosuppressive potential of GP, which is composed largely of MAN, was found to be dependent upon the presence of its heat-labile protein moiety.

In vivo effects of human dialyzable leukocyte lysate. III. Modulation of the spleen cell proliferative response to antigen by components of leukocyte dialysates and an initial characterization of an ampliative nucleoside

The augmentative effects of isolated components of human dialyzable leukocyte lysates upon the proliferative response to antigen were investigated. Sequential Sephadex G-25 and Bio-Gel P-4 chromatography separated five distinct fractions which, 24 hr after injection into Keyhole limpet hemacyanin (KLH)-sensitive mice, either augmented or suppressed the in vitro spleen cell proliferative response to KLH. An amplifier molecule was isolated from one of the augmentative fractions by high-pressure, reverse-phase liquid chromatography. Preliminary structural analysis of the amplifier component indicated a nucleoside structure, similar to--but possibly distinct from--thymidine.

Clinical and immunologic response to antigen-specific transfer factor in drug-resistant infection with Mycobacterium xenopi

The administration of transfer factor obtained from three donors who had recovered from clinical infections with Mycobacterium xenopi to a patient who had a destructive pulmonary infection with this organism, was associated with the reversal of an unfavorable clinical course. Cavitary tuberculosis associated with resistance to all combinations of antituberculosis drugs was probably related to a concurrent depression of cell-mediated immunity of unknown origin. Antigen specific but not nonspecific transfer factor caused a rapid and prolonged improvement in both the pulmonary disease and the immunologic deficiency. Cross-reactivity between the antigenic determinants of M. xenopi and Mycobacterium tuberculosis made it possible to use transfer factor obtained from donors responsive to purified protein derivative of tuberculin. This study clearly demonstrates the additional benefits to be gained from using transfer factor that is antigen-specific in the treatment of infectious diseases.

Chromoblastomycosis. A morphological investigation of the host-parasite interaction

Chromoblastomycosis is a distinct cutaneous mycotic infection. Histologically it is characterized by the presence of fungus invariably in the yeast phase and by macrophages in large numbers. The morphology of fungus in both yeast and hyphal phases and its interaction with mononuclear phagocytes were examined using ultrastructural techniques. The major structural difference between the fungus in cutaneous tissue and that from a culture medium was a striking increase in cell wall thickness in the former. In the skin, the organisms were phagocytised by macrophages and enclosed in large membrane limited intracytoplasmic vacuoles. The thick, stratified, electron-dense fungal cell wall was observed in stages of alteration of varying severity. Most common was a granular modification of the outermost layers of the cell wall in contact with the vacuolar content. Fragmentation, splitting and rupture of this and deeper layers was also seen. Several ultrastructural features suggested that cell wall damage resulted from an active host cell digestion. The cell wall changes were in sharp contrast with the usual normal fungal cytoplasmic appearance. Only rare intracellular debris which we supposed to represent dead yeast cells were found. These findings suggested that the yeast responsible for chromoblastomycosis resisted fungicidal activities of cutaneous macrophages which possessed the ultrastructural features of stimulated phagocytes.

Disseminated coccidioidomycosis in children

In an effort to define the importance of extrapulmonary coccidioidomycosis in the pediatric age group, we have studied 14 cases and reviewed the literature. The available data suggest that children are as susceptible to dissemination as are adults. Most children with disseminated coccidioidomycosis have evidence, either by history or chest radiographs, of preceding or concurrent pulmonary infection. The most common sites of dissemination are skin, subcutaneous tissue, bone, and meninges. Coccidioides immitis may be detected in tissues or body secretions by microscopic examination or by appropriate culture. Serologic tests are also useful in making the diagnosis and in following the course of the infection. Skin tests are often negative. Infection is progressive in 60% without antifungal therapy. Coccidioidomycosis of bone, skin, or subcutaneous tissue can be managed effectively with combined surgical and antifungal therapy. Meningitis is much more difficult to treat and is fatal in 50% of cases even when treated with amphotericin B.

Transfer factor

The understanding of passive transfer of cell mediated-immune responses with transfer factor and other cell free materials has progressed to the point that investigators are seeking the chemical identity of the molecule(s) that are responsible for these effects and are working on their mechanisms of action. In addition, clinical trials are underway that should clarify the potential for use of transfer factor in treatment of infections, neoplastic and autoimmune diseases. This chapter will critically review the past and current data concerning the components of transfer factor and their effects on immunologic and inflammatory reactions. Some of the recently developed animal models will be described and evaluated, and the clinical studies that have provided conclusive data regarding efficacy will be reviewed.

Transfer factor in immunodeficiency diseases

Results of therapeutic trials of transfer factor in a number of laboratories suggest clinical benefit and enhancement of immunological reactivity in patients with primary or secondary immunodeficiency diseases. Long term follow-up of 32 patients with the Wiskott-Aldrich syndrome suggested that transfer factor caused conversion of immunologic reactivity, apparent clinical benefit, and prolonged survival in some, but not in all patients. In 18 patients with disseminated (Stage III) malignant melanoma treated with surgery and transfer factor, survival was better than would ordinarily be expected for disseminated disease (78% with mean follow-up of 2 years). A randomized trial has been initiated which will answer the question of the efficacy of transfer factor as surgical adjuvant therapy in malignant melanoma. Studies in human subjects suggested that transfer factor does not cause enhancement of reactivity in normal subjects, when evaluated in a controlled, double-blind fashion. Similar controlled studies in immunodeficient patients are necessary to ascertain whether transfer factor does cause enhancement of immune responses in these patients. Based on these observations, a guinea pig model was developed in which transfer factor caused abrogation of tolerance to ABA-Tyrosine.

[Transfer factor (TF) treatment of patients with HBs-Ag-positive chronic active hepatitis. A prospective, controlled study (author's transl)]

It is a clinically and experimentally well supported working hypothesis that infection with hepatitis B virus may result in chronic active hepatitis in patients with suspected immune deficiencies. On this basis, a pilot study was performed in order to evaluate the effect of "specific" transfer factor (TF) in the treatment of HBS-Ag-positive chronic active hepatitis. From the leukocytes of 500 ml venous blood each of 40 volunteers that had completely recovered from acute virus hepatitis B within the last 6 months, a unique TF pool (40 units of TF) was prepared according to the method of Lawrence. Preexaminations indicated that this preparation was able to enhance cellular immune reactions in vitro. Thirteen patients with HBS-antigenemia and chronic active hepatitis (i.e., two liver biopsies within the last 6 or more months with the histological criteria of chronic aggressive hepatitis according to de Groote, elevated serum levels of bilirubin, alkaline phosphatase, transaminase activities, and/or gamma-globulines) were randomized: Seven received s.c. injections of two units of TF each on days 1 and 15, the other six saline. Conversion of skin reactions to some ubiquitous antigens occurred in the TF group, but no significant and constant drop of HBS-Ag serum titers was observed. Although some of the biochemical parameters seemed to ameliorate in the TF group, the differences versus the control group did not prove to be significant within the limited number of patients under observation. The in vitro reactivity of patients' lymphocytes to HBS-Ag, tested by means of the 3H-thymidine uptake, was never found enhanced after TF application. In the used doses, "specific" TF was not effective in the treatment of HBS-Ag-positive chronic active hepatitis; unfavorable side-effects were not observed.

Cell-mediated immune responses in mice infected with Fonsecaea pedrosoi

Time course of cellular and humoral immune responses in mice infected with Fonsecaea pedrosoi was investigated by using an antigen prepared from culture filtrate of this fungus. Mice were infected by intravenous injection with yeast-like cells of the fungus. Viable fungus was recovered from the brain of the infected mice until the 36th day after inoculation, and from the other organs examined until 14th to 16th day. Inflammatory lesions were observed in the brain, lung, heart, liver, spleen, kidney and intestine during the first 30 days after inoculation. Macrophage migration inhibition factor response in these mice was insignificant until 8 days after inoculation. A significant response was developed at day 10 and persisted until day 63. This response returned negative by 95 days after inoculation. Lymphocyte transformation response of these mice was negative until 4 days after inoculation. At day 6 blastogenic index increased to 1.5, and at day 10, 14 and 16 the indices were 1.8, 2.4 and 1.7 respectively. Precipitin response to this fungus could not be detected in these mice until 16 days after inoculation, Positive results were obtained at day 21 and lasted until 51 days after inoculation. The precipitin titers, however, did not exceed one fold in any of these mice.

A study of transfer factor for opportunistic infections in cancer patients

Although supportive care during therapy of patients with malignancies has improved, infection remains the major cause of death in these patients. The problem of "opportunistic" infections is becoming more apparent as better antibiotics are found. The control of these infections depends in part on mechanisms of cell-mediated immunity. It has been demonstrated that delayed-type hypersensitivity can be transferred from one person to another. Therefore, we used transfer factor in the treatment of 15 patients, most with leukemia, who had fungal, viral, or mycobacterial infections that were not responding to conventional therapy. Seven of ten evaluable patients had therapeutic control of their infections while receiving transfer factor. Transfer factor appears to have contributed to these clinical improvements and is a modality of treatment that deserves further investigation.

Miconazole for treatment of disseminated coccidioidomycosis. Unfavorable experience

Miconazole at dosages up to 30 mg/kg/day was given intravenously to seven patients with complicated courses of disseminated coccidioidomycosis. Six had received treatment with amphotericin B previously and five of these patients could be evaluated for the efficacy of the treatment. In three patients the condition failed to respond to therapy, another patient required intratracheal administration of amphotericin B later, and the fifth patient had an equivocal response to treatment. Severe phlebitis, pruritus, nausea, vomiting, hyperlipidemia, and thrombocytosis were frequent side effects. These limited unfavorable results indicate that until controlled studies demonstrate its safety and efficacy, therapy with miconazole should be reserved for highly selected patients with disseminated coccidioidomycosis who cannot receive amphotericin B.

Disseminated coccidioidomycosis: clinical, immunologic and therapeutic aspects

A patient with disseminated coccidioidomycosis initially had pulmonary and skin manifestations and survived for 14 years before dying of meningitis due to Coccidioides immitis. In addition to several courses of amphotericin B therapy the patient received injections of transfer factor derived from appropriate donors and miconazole nitrate therapy. The immunologic defence mechanisms of the patient during the course of his disease were studied and the possibility of a cell-mediated immunologic defect, potentially reversible by transfer factor, was demonstrated.

In vitro lymphocyte responses of coccidioidin skin test-positive and -negative persons to coccidioidin, spherulin, and a coccidioides cell wall antigen

The biological activity of C-ASWS, an alkali-soluble, water-soluble cell wall antigen isolated from mycelial-phase cells of Coccidioides immitis, was compared with that of a commercial coccidioidin (CDN; Cutter Laboratories); CDN-TS, a toluene-induced lysate of mycelial-phase cells; and spherulin, a spherule-derived extract of C. immitis. Lymphocytes obtained from healthy CDN skin test-positive donors (group I), healthy skin test-negative donors (group II), and patients with active coccidioidomycosis (group III) were assayed for lymphocyte transformation and production of macrophage inhibitory factor in response to the Coccidioides antigens. C-ASWS, CDN CDN-TS, and spherulin were each effective in eliciting blastogenic responses in lymphocytes of group I subjects. However, only C-ASWS and CDN-TS were effective in eliciting macrophage inhibitory factor production. The responses of group III subjects (patients) were depressed and, in most instances, were indistinguishable from those obtained in lymphocytes of group II subjects.

Pulmonary mycetoma due to Coccidioides immitis

Pulmonary mycetoma due to Coccidioides immitis has been reported on three occasions. The present case is the fourth such report occurring in a patient with widely disseminated disease. Spherules and hyphae were found in the specimen. While the active pulmonary and extra-pulmonary lesions responded well to therapy with amphotericin B, resection was required to eliminate the residual mycetoma and its attendant hemoptysis.

Transfer factor: a potential agent for cancer therapy

This review has attempted to describe the characteristics of transfer factor which make it a very attractive potential agent for immunotherapy. Preliminary observations suggest that it may be capable of modifying resistance to a variety of diseases including cancer but considerable progress in basic knowledge regarding this agent is crucial to its successful application in clinical disease states. Fortunately, a sizable number of interested and dedicated investigators are exploring these difficult problems and their success may lead to new approaches in immunotherapy.

Suppressor thymus-derived lymphocytes in fungal infection

Thymus-derived lymphocyte (T-cell) function, as determined in vivo by cutaneous reactivity to several antigens and in vitro by responsiveness to mitogens and antigens, was assessed in 14 patients infected with a variety of fungal organisms. While all patients manifested a normal frequency of peripheral blood T cells, only seven patients reacted to at least one of the antigens used for cutaneous testing and demonstrated normal in vitro T proliferative responses. Three patients exhibited cutaneous anergy but normal in vitro T-cell reactivity while four patients demonstrated persistent anergy and marked in vitro T-cell hyporeactivity which was independent of activity of infection, concurrent medication, or any associated disorders. The marked diminution of in vitro T-cell reactivity noted for these later four patients was not due to a deletion of antigen- or mitogen-reactive cells. Thus, patients' cells which had been initially cultured for 7 days without any mitogenic or antigenic stimulus and which were subsequently washed and recultured with phytohemagglutinin, concanavalin A, or histoplasmin demonstrated a marked increase in their responsiveness. Moreover, this reactivity noted for recultured cells could be suppressed by a nonphagocytic, nonadherent, nonimmunoglobulin-bearing, sheep red blood cell rosette-forming population of cells isolated from the fresh peripheral blood mononuclear cells of the same patient. While these "regulator" T cells were capable of suppressing T-proliferative responses to antigens and mitogens, they did not diminish pokeweed mitogen-induced immunoglobulin synthesis by normal bone marrow-derived lymphocytes. Patients in whom suppressor "T" cells were found were at risk for relapsing, disseminated fungal infection.

Miconazole in coccidiodomycosis. II. Therapeutic and pharmacologic studies in man

Fourteen patients with chronic coccidioidomycosis, many of whom had complicating concurrent diseases and/or had failed to respond to amphotericin therapy, were treated with intravenous miconazole, a synthetic imidazole drug previously shown to be effective in experimental murine coccidioidomycosis. Up to 3.6 g/day was given for up to three months. 7inimal inhibitory concentrations of mycelial and endospore phases of all clinical isolates of C. immitis were less than 2.0 mug/ml. Peak concentrations in the blood of up to 7.5 mug/ml (by assay against C. immitis in vitro) were achieved. Doses above 9 mg/kg or 350 mg/m2 were more efficacious in producing blood levels over 1 mug/ml. Serum protein binding, determined by several methods, was approximately 90 per cent. The disappearance of bioactive drug from blood after infusion has a rapid initial phase (t1/2 approximately 30 minutes) and a final plateau (t1/2 approximately 20 hours). Eight patients had objective evidence of response, three had slight or equivocal responses, two could not be evaluated, and one was a treatment failure. Side effects were generally uncommon, minor and transient except for phlebitis. Infusion into central venous catheters appears to circumvent this problem. Miconazole is a potentially useful drug in the treatment of coccidioidomycosis.

Disseminated histoplasmosis and necrotizing vasculitis

A 74-year-old man with congestive heart failure was found to have Histoplasma capsulatum in a lesion of the right nasal septum. His initial treatment with amphotericin B was inadequate because of severe intolerance to the drug. Three months after initial presentation H. capsulatum was detected in his blood and bone marrow. Slightly elevated purpuric lesions on the arms, lower legs and trunk showed the typical features of necrotizing vasculitis. Cutaneous anergy was reversed after treatment with transfer factor. Skin involvement in disseminated histoplasmosis is unusual and there are no previous reports of vasculitis associated with this infection.

Transfer factor preparations: some physico-chemical and biological properties

Some biological and physico-chemical properties were tested in 50 lots of transfer factor (TF). Each lot contained the extracts of a pool of 20 buffy coats, each originating from a 400 ml blood donation of a healthy individual. The optical densities at 260 and 280 nm were within a narrow range in all TF lots. The ratio 260/280 was 2.56-3.02. One unit TF (defined as the extract of two buffy coats (corresponding to 1-2 X 10(9) leucocytes) contained 36.58 +/- 3.77 mg of peptides as measured by the Lowry method and 123.6 +/- 4.5 mg ribose as estimated by the orcinol method. Cytotoxicity of TF lots was tested by measurement of chromium release of PHA-stimulated lymphocytes. Cytotoxicity was above 10% in 20 of 27 TF lots tested, most of which were produced by an Amicon ultrafiltration cell. Pyrogenicity was present in 8 of 42 TF lots produced by Amicon filters, but only in 1 of 8 lots produced by Sartorius filters. Sephadex G-10 chromatograms of TF gave characteristic patterns yielding 8 peaks. Sephadex G-25 chromatograms reproducibly showed 5 peaks. The distribution of osmotic activity, peptides and ribose in respect of the chromatographic fractions is given.

Stimulation of monocyte cGMP by leukocyte dialysates. An antigen-independent property of dialyzable transfer factor

We studied the effects of dialysates from leukocyte lysates containing dialyzable transfer factor activity and other leukocyte dialysates devoid of transfer factor activity on accumulation of cyclic nucleotides in human leukocytes. Dialysates from normal leukocytes produced 4- to 11-fold increases in leukocyte cGMP, and experiments with purified cell populations revealed that the increases were predominantly, if not entirely, in blood monocytes. Substances that increased monocyte cGMP could be obtained from several cell populations including mononuclear cells from Hypaque-Ficoll gradients, plastic-adherent monocytes, nonadherent lymphocytes, and neutrophils, but were not present in dialysates of leukemic lymphocytes from patients with the Sezary syndrome. Moreover, dialysates that increased leukocyte cGMP had essentially no effect on intracellular cAMP. Dialysates of lysed mononuclear cells contained serotonin, ascorbate, and an unidentified cholinergic activity, agents known to increase leukocyte cGMP. After passage of dialyzable transfer factor from mononuclear cells through a gel-filtration column, four fractions were obtained that increased leukocyte cGMP. Two of these fractions contained ascorbate; two other active fractions, including one that also caused conversion of delayed skin tests, did not contain detectable ascorbate or serotonin. The dialysate of lysed neutrophils also increased cGMP, but this activity was limited to the column fractions which contained ascorbic acid. These observations raise the possibility that alterations in monocyte cGMP content could modulate either the specific antigen-dependent, or, more likely, the antigen-independent activities in preparations of transfer factor.