Adenoviral vector encoding soluble Flt-1 engineered human endometrial mesenchymal stem cells effectively regress endometriotic lesions in NOD/SCID mice.

This study was undertaken to study the efficiency of Adsflt-1 engineered human eutopic mesenchymal stem cells (MSCs) secreting anti-angiogenic sFlt-1 as a targeted cell-based therapy for endometriosis (EM). Eutopic MSCs were transduced with Adsflt-1/AdV0 viral vectors and were evaluated for expression and secretion of sFlt-1. EM was created in NOD/SCID mice using subcutaneous implantation techniques. Four doses of 10(6) MSC-Adsflt-1/MSC-AdV0 were administered to the model and therapeutic anti-angiogenic ability was analyzed by lesion size measurement, microvessel density, immunohistochemistry and real-time reverse transcriptase-PCR analysis. Approximately 86% of transduced MSCs expressed and secreted sFlt-1. MSC-Adsflt-1-treated animals exhibited significant reduction (52.8±1.8%) in size of endometriotic lesions. We observed a 2.3-fold decrease in the number and a 10-fold decrease in the size of endometrial glands in MSC-Adsflt-1-treated animals. A two-fold decrease in stromal cell densities was also observed in MSC-Adsflt-1-treated animals compared with the MSC-AdV0 group. Specific positive immunostaining for MSC marker, CD146 and sFlt-1 in the lesion sites of the MSC-Adsflt-1 group suggests possible homing of transduced MSCs, their survival and secretion of sFlt-1 at the target sites. A marked reduction in size of microvessels and microvessel density within endometriotic lesions and surrounding host subcutaneous layers was observed in MSC-Adsflt-1 group along with significantly downregulated expression of transcripts for vascular endothelial growth factor, fetal liver kinase 1 and matrix metalloproteinases (2 and 9). Our findings indicate the efficacy of a novel eutopic MSC-Adsflt-1 therapy in EM study models. Evaluating long-term effects of genetically modified MSCs in vivo is essential in translating MSC-Adsflt-1 therapy to the clinics.

Surfactant proteins A and D protect mice against pulmonary hypersensitivity induced by Aspergillus fumigatus antigens and allergens.

Allergic bronchopulmonary aspergillosis (ABPA) is an allergic disorder caused by an opportunistic fungal pathogen, Aspergillus fumigatus (AFU:). Lung surfactant proteins SP-A and SP-D can interact with the glycosylated antigens and allergens of AFU:, inhibit specific IgE binding to these allergens, and block histamine release from sensitized basophils. We have now examined the therapeutic effect of exogenous administration of human SP-A, SP-D, and a recombinant fragment of SP-D (rSP-D), in a murine model of pulmonary hypersensitivity induced by AFU: antigens and allergens, which resembles human ABPA immunologically. The ABPA mice exhibited high levels of AFU:-specific IgG and IgE, blood eosinophilia, extensive infiltration of lymphocytes and eosinophils in the lung sections, and a Th2 cytokine response. Treatment with SP-A, SP-D, and rSP-D lowered blood eosinophilia, pulmonary infiltration, and specific Ab levels considerably, which persisted up to 4 days in the SP-A-treated ABPA mice, and up to 16 days in the SP-D- or rSP-D-treated ABPA mice. The levels of IL-2, IL-4, and IL-5 were decreased, while the level of IFN-gamma was raised in the splenic supernatants of the treated mice, indicating a marked shift from Th2 to Th1 response. These results clearly implicate pulmonary SP-A and SP-D in the modulation of allergic reactions.

Expression and localization of collectins in feto-maternal tissues of human first trimester spontaneous abortion and abortion prone mouse model.

Dysregulation of immune response at the feto-maternal interface during first trimester of pregnancy is one of the leading causes of spontaneous abortion. Previously, we reported differential expression of collectins, soluble pattern recognition molecules involved in immunoregulation, in placental and decidual tissues during spontaneous labor. In the present pilot study, the expression of collectins was analyzed in the inflamed human gestational tissues of spontaneous abortion ('SA') and in 13.5 dpc placental tissues from resorption survived embryos of murine model (CBA/J X DBA/2J). Transcripts of SP-A were significantly down-regulated and SP-D were significantly up-regulated in placental and decidual tissues of 'SA' group compared to that of 'normal' group. Immunostaining for SP-D and MBL proteins was positive in placental and decidual tissues. However, levels of SP-D and MBL proteins were not significantly altered in placental as well as in decidual tissues of 'SA' group in comparison to the 'normal' group. Placental tissues of viable embryos from the abortion prone mouse model showed significantly enhanced expression of mSP-A and mSP-D transcripts at 13.5 day post coitus (dpc) and 14.5 dpc compared to the control group (CBA/J X Balb/c). Mouse collectins were localized in placental tissues (13.5 dpc), with increased staining in murine model compared to control. Human and murine data together indicate that SP-A, SP-D and MBL are synthesised in early gestational tissues, and may contribute to regulation of immune response at the feto-maternal interface during pregnancy.

Expression of an epitopic region of AspfI, an allergen/antigen/cytotoxin of Aspergillus fumigatus.

The gene for an 18 kD allergen/cytotoxin of Aspergillus fumigatus was cloned in pUC-19 vector and expressed in Escherichia coli JM109. Digestion of this gene with AluI resulted in four fragments of 216bp, 120bp, 39bp and 21bp. These fragments were cloned in the Sma-I site of pUC-19. The recombinants thus, generated after transformation in E. coli JM109, were screened using monoclonal antibodies raised against the AspfI. The fusion protein containing 120 bp AluI fragment was recognised by the MoAb indicating presence of epitope(s) in the 120 bp region. The study indicates a viable strategy for identification and expression of an immunologically active domain of a major allergen/antigen of A. fumigatus for the first time.

Dying with dignity.

Death is a theme of central importance in all cultures, but the manner in which it is interpreted varies from society to society. Even so, traditional cultures, including Christian, Hindu and Jain religious traditions, exhibited a positive attitude to death and did not look upon it in a dualistic framework of good vs bad, or desirable vs undesirable. Nor was pessimism the dominant mood in their thinking about death itself. A fundamental paradigm shift occurred in the West in the eighteenth century when death was desacralized and transformed into a secular event amenable to human manipulation. From those early beginnings, dying and death have been thoroughly medicalized and brought under the purview of high technology in the twentieth century. Once death is seen as a problem for professional management, the hospital displaces the home, and specialists with different kinds and degrees of expertise take over from the family. Everyday speech and the religious idiom yield place to medical jargon. The subject (an ageing, sick or dying person) becomes the object of this make-believe yet real world. As the object of others' professional control, he or she loses the freedom of self-assessment, expression and choice. Or, he or she may be expected to choose when no longer able to do so. Thus, not only freedom but dignity also is lost, and lawyers join doctors in crisis manipulation and perpetuation. Although the modern medical culture has originated in the West, it has gradually spread to all parts of the world, subjugating other kinds of medical knowledge and other attitudes to dying and death.(ABSTRACT TRUNCATED AT 250 WORDS)

Community involvement in health policy; socio-structural and dynamic aspects of health beliefs.

The notion of community involvement in health, as in fact in schemes of community welfare generally, has found wide acceptance in all kinds of political regimes and particularly in the Third World countries. Such involvement is expected not only to be cost-effective but, more importantly, the best way of providing comprehensive solutions to public health problems. More than 50 years of experience with schemes of community participation in India, however, show that the enthusiasm of the people generally tends to wane after a short period of time. Nevertheless, efforts at community involvement in health continue to be made. Governmental and non-governmental organizations and UN agencies, notably WHO, have been active in promoting the concept. The 1978 Alma Ata declaration on primary health care strongly emphasized the right and duty of people to plan and implement health care programmes. Even so, many operational problems remain and these are perhaps related partly to a lack of conceptual clarity. Ideally, community involvement should mean that the initiatives come from the people and the government and other agencies provide assistance. In reality, however, this rarely is so. The best that may be expected is that people will come forward voluntarily to participate in public health programmes. Generally, however, their co-operation has to be sought and they have to be motivated to participate in health schemes. Involvement could also be brought about through coercive measures but there is little support for such an approach, though many health programmes (such as that of small pox vaccination) have been known to have depended upon compliance for their success.(ABSTRACT TRUNCATED AT 250 WORDS)

Multifunctional antigens of A. fumigatus and specific antibodies.

The majority of Aspergillus-induced infections in man are caused by the pathogenic fungus A. fumigatus, which secretes biologically and immunologically active glycosylated and nonglycosylated proteins. The complexity in the antigenic structure of A. fumigatus and the varying host immune responses lead to a wide spectrum of clinical conditions such as allergic bronchopulmonary aspergillosis (ABPA), aspergilloma, and invasive aspergillosis. It is reported that 15-20% of allergic asthmatics suffer from Aspergillus-induced allergies. The incidence of opportunistic infections, including Aspergillus infections, has risen because of the increase in the incidence of HIV and tuberculosis. Allergic bronchopulmonary aspergillosis is an immunologically significant clinical form where type I and type III hypersensitivity reactions are involved in pathogenesis. High levels of specific IgE and IgG antibodies in these patients are of diagnostic value. Molecular characterization of certain immunodominant allergens and antigens of A. fumigatus revealed the presence of complex carbohydrate moieties, heat-shock proteins, enzyme activities such as elastase, protease, catalase, dismutase, and cytotoxic ribonuclease. A Con A binding allergen/antigen (45 kDa) and Con A nonbinding allergen/antigen (18 kDa, Asp fI) have a multifunctional nature. The multifunctional nature of these antigens may play an important role in the pathogenesis of the disease. Significant amounts of a major allergen/antigen of molecular weight 18 kDa is excreted in large amounts through the urine of patients with invasive aspergillosis. Studies on the structure-function relationship of the 18-kDa allergen/antigen revealed the involvement of tryptophan residues in binding with monoclonal antibodies (MAbs). Also, the histidine residues and cysteine disulfide bonds of the 18-kDa allergen are involved in its catalytic activity. The high load of multifunctional antigens in the serum of patients for prolonged periods, the presence of high levels of specific antibodies, and the absence of protective antibodies in ABPA patients have necessitated studies on the functional properties of the antibodies. The present study shows significant immunoreactivity of antibodies in patients of ABPA to fibronectin and collagen. Analysis of IgG antibodies from the patients of ABPA showed the presence of DNA-cleaving activity. These observations offer a new line of thinking in understanding the mechanism of pathogenesis of Aspergillus-induced clinical manifestations, and may lead to novel approaches to intervention in the inflammation and infection caused by fungal pathogens.

Challenges in prevention, diagnosis and therapy of emerging fungal diseases. Aspergillosis: A case study.

Diseases caused by pathogenic filamentous fungi, are an emerging threat to public health in the wake of increasing incidence of HIV and tuberculosis. At this point, discovery and development of fungal therapeutics and diagnostics are serious challenges for biomedical researchers. Recent technological advances in genomics and proteomics offer great scope for development of preventive and therapeutic measures for fungal diseases.Aspergillus, one of the medically important filamentous pathogenic fungi causes a wide spectrum of clinical disorders ranging from allergic aspergillosis to systemic invasive aspergillosis. Increase in incidence of drug resistance and the cytotoxic effects are two serious limitations of the antifungal drugs presently in use. This is primarily due to lack of understanding of biological mechanisms operative in these fungi. Today, it is possible to understand the biological mechanisms of the fungus for its colonisation, survival and invasion of the host. Future developments based on such leads can result in development of precise and specific diagnostic, therapeutic and preventive measures for a wide clinical spectrum of fungal diseases.

Identification of novel allergens of Aspergillus fumigatus using immunoproteomics approach.

BACKGROUND: Approximately 20% of the world's asthmatics are suffering from Aspergillus fumigatus (Afu)-induced allergies. The characterization of specific IgE-inducing allergens in allergic aspergillosis patients is fundamental for clinical diagnosis and for immunotherapy. METHODS: Immunoproteomics combined with mass spectrometric analysis was used to identify proteins of third-week culture filtrate (3wcf) potentially responsible for Afu-specific IgE immunoreactivity, using pooled sera from Afu-sensitized asthmatics. Their allergenic potential was also tested against patients with allergic bronchopulmonary aspergillosis (ABPA), by two-dimensional (2-D) gel electrophoresis immunoblotting of 3wcf proteins with individual sera from such patients. This helped us to establish a set of candidate allergens, which could be explored further for diagnostic application in allergic aspergillosis asthmatics including ABPA. RESULTS: Peptide mass fingerprint using matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and/or de novo sequencing by MS/MS analysis of the protein spots from 2-D gels led to the identification of a total of 16 allergens of Afu. Eleven of them are being reported as allergens for the first time and five had been reported earlier. Putative isoforms of the proteins Asp f 13 and chitosanase have been observed for the first time. When studied for reactivity of these proteins among patients with ABPA using their individual sera, these patients exhibited sensitization although the pattern was varying. Taken together, these proteins could thus be considered as potential allergens even among patients with ABPA. Three of these proteins viz. the hypothetical protein (# spot no. 5), extracellular arabinase (# spot no. 6) and chitosanase (# spot no. 11) could be major allergens with specific IgE immunoreactivity with six out of eight patients' sera. CONCLUSIONS: The immunoproteomic approach applied to the analysis of culture filtrate proteins resulted in the identification of several candidate allergens, many of them novel, contributing to the catalogue of Afu allergenic proteins, which would facilitate improved serodiagnosis for allergic aspergillosis. In addition, the immunoreactivity of these proteins observed among the patients with ABPA may be potentially useful for its serodiagnosis and opens up further opportunities for the development of personalized immunotherapeutics for patients with ABPA.

Protective role of mannan-binding lectin in a murine model of invasive pulmonary aspergillosis.

Innate immune molecules such as lung collectins and serum pentraxins have evolved as important host defence proteins against Aspergillus fumigatus, a medically important opportunistic fungal pathogen. Mannan-binding lectin (MBL), an opsonin and lectin complement pathway activator, constitutes another vital player of innate immunity against several pathogenic organisms in the serum. Studies have reported significant binding of MBL to A. fumigatus; however, the protective role of MBL against A. fumigatus-mediated invasive disease remains elusive. Henceforth, we investigated the contribution of externally administered recombinant human (rh) MBL towards anti-fungal defence in invasive pulmonary aspergillosis (IPA) by in vivo and in vitro studies. In murine models of IPA with corticosteroid-induced immunosuppression, rhMBL-treated mice showed 80% survival compared to untreated IPA mice with no survivors. Treated IPA mice also showed a marked increase in tumour necrosis factor (TNF)-alpha and interleukin (IL)-1alpha and a significant decrease in pulmonary fungal hyphae and IL-10. In vitro, rhMBL-bound A. fumigatus conidia showed a dose-dependent increase in the deposition of C4b, the first product of the lectin pathway. There was an enhanced uptake of A. fumigatus conidia by the polymorphonuclear cells (PMNs) in the presence of rhMBL that increased further in the presence of MBL supplemented with MBL-deficient serum. However, an increase in the oxidative burst of PMNs and A. fumigatus killing were observed only when MBL was supplemented with MBL-deficient serum. The study suggests a therapeutic role of ex vivo-administered MBL in host defence against aspergillosis, possibly through MBL-mediated complement activation and other protective mechanisms aimed both directly at the pathogen, and indirectly through modulation of the host inflammatory responses.

Elevated levels of mannan-binding lectin [corrected] (MBL) and eosinophilia in patients of bronchial asthma with allergic rhinitis and allergic bronchopulmonary aspergillosis associate with a novel intronic polymorphism in MBL.

Mannan-binding lectin (MBL), an important component of innate immunity, binds to a range of foreign antigens and initiates the lectin complement pathway. Earlier studies have reported high plasma MBL levels in allergic patients in comparison to healthy controls. In view of varied plasma MBL levels being determined by genetic polymorphisms in its collagen region, we investigated the association of single nucleotide polymorphisms (SNPs) in the collagen region of human MBL with respiratory allergic diseases. The study groups comprised patients of bronchial asthma with allergic rhinitis (n = 49) and allergic bronchopulmonary aspergillosis (APBA) (n = 11) and unrelated age-matched healthy controls of Indian origin (n = 84). A novel intronic SNP, G1011A of MBL, showed a significant association with both the patient groups in comparison to the controls (P < 0.01). Patients homozygous for the 1011A allele showed significantly higher plasma MBL levels and activity than those homozygous for the 1011G allele (P < 0.05). The 1011A allele also showed a significant correlation with high peripheral blood eosinophilia (P < 0.05) and low forced expiratory volume in 1 s (FEV(1)) (P < 0.05) of the patients. We conclude that the 1011A allele of MBL may contribute to elevated plasma MBL levels and activity and to increased severity of the disease markers in patients of bronchial asthma with allergic rhinitis and ABPA.

Role of collectins in innate immunity against aspergillosis.

The protective role of lung surfactant proteins SP-A, SP-D and MBL in the host defense against both allergic and invasive aspergillosis was identified and established by a series of in vitro and in vivo studies. Therapeutic administration of SP-D and MBL proteins in a murine model of pulmonary invasive aspergillosis rescued mice from death. In mice mimicking human allergic bronchopulmonary aspergillosis, SP-A and SP-D suppressed IgE levels, eosinophilia, pulmonary cellular infiltration and cause a marked shift from a pathogenic Th2 to a protective Th1 cytokine profile. SP-A and SP-D knock-out mice studies made significant contributions in understanding the mechanisms by which SP-A and SP-D modulate the host defense response in patients suffering from pulmonary allergies and infections. The results suggested that individuals with any structural or functional defects in these innate immune molecules due to genetic variations might be susceptible to aspergillosis. SNPs in SP-A2 and MBL genes showed significant associations with patients of allergic bronchopulmonary aspergillosis in an Indian population. The patients carrying either one or both of GCT and AGG alleles of SP-A2 and patients with A allele at position 1011 of MBL had markedly higher eosinophilia, total IgE antibodies and lower FEV1 (the clinical markers of ABPA). Our results show that collectins play an important role in Aspergillus mediated allergies and infections.

Identification and evaluation of a major cytotoxin of A. fumigatus.

Aspergillus fumigatus is a highly pathogenic fungus causing a wide spectrum of diseases in immunocompromised as well as immunocompetent hosts. The present work was undertaken to evaluate the cytotoxic nature of fractionated antigens of A. fumigatus against the mammalian cell lines (J774, RAW, CHO and L929). An enriched protein antigenic fraction of A. fumigatus was subjected to con A Sepharose and phenyl Sepharose chromatography. Antigenic fractions, ConAub (conA unbound) and PSC III (fraction III of phenyl Sepharose column) containing low mw antigens showed higher cytotoxicity as compared to other antigenic fractions. PSC III was further purified on HPLC resulting in an 18 kDa homogeneous protein. The purified protein showed high ELISA absorbance values for specific IgG and IgE antibodies in sera of ABPA patients. Monoclonal antibody raised against Asp fl, a major allergen/antigen of A. fumigatus recognised the purified 18 kDa by ELISA and western blot. The 18 kDa allergen/antigen or Asp fl showed similar toxicity towards all the four cell lines (macrophage and fibroblast) with an IC50 of 75 ng/ml or 4.16 nM. Reduction in toxicity of 18 kDa at low temperatures and potentiation in presence of ammonium chloride and monensin indicates mechanism of internalisation of 18 kDa in eukaryotic cells is similar to alpha-sarcin. The present work shows that the 18 kDa allergen/antigen (Asp fl) is a major cytotoxin secreted by A. fumigatus which may play multiple roles in the pathogenesis of Aspergillosis through allergenicity, antigenicity and cytotoxicity.

Ribonuclease activity dependent cytotoxicity of Asp fl, a major allergen of A. fumigatus.

A major allergen/antigen, Asp fl, secreted by Aspergillus fumigatus exhibits cytotoxicity towards eukaryotic cell lines. Asp fl inhibited protein synthesis in RAW cells with an IC50 of 4.5 nM and also degraded ribosomal RNA of RAW cells at a similar concentration. Ribosomal inactivation by Asp fl may be the probable mechanism for protein synthesis inhibition. Specific ribonuclease activity of Asp fl was observed to be 100,000 U/mg. Presence of strong RNase activity in Asp fl was further confirmed by agar gels containing yeast RNA. Electrophoretic run on agarose gels showed that Asp fl degrades all species of naked RNA. Modification of histidine residues of Asp fl with diethyl pyrocarbonate and alkylation of cysteines with iodoacetamide resulted in loss of ribonuclease activity and cytotoxicity of Asp fl. The current study establishes the ribonuclease activity of a purified major allergen of A. fumigatus that inhibits protein synthesis and kills the eukaryotic cells.

cDNA cloning, expression and characterization of an allergenic L3 ribosomal protein of Aspergillus fumigatus.

Aspergillus fumigatus (Afu) is an important fungal pathogen causing allergic and invasive respiratory disorders. A plethora of multi-functional allergens/antigens secreted by Afu have been implicated in pathogenesis. The present study was undertaken to identify and characterize novel Afu allergen/antigen by cDNA library approach. cDNA library of Afu was immunoscreened with pooled sera of allergic bronchopulmonary aspergillosis (ABPA) patients. The cDNA clone, TS1, reacting significantly with specific IgG antibodies, was selected. cDNA was subcloned and expressed in Escherichia coli. Sequencing of the cDNA revealed an open reading frame (ORF) of 1179 bases coding for a protein with an approximate molecular weight of 44 kDa. Immunoreactivity of the recombinant TS1 protein (rTS1) was evaluated by ELISA and Western blot analysis using pooled sera of ABPA patients. The rTS1 exhibited binding to specific IgG and IgE antibodies present in sera of ABPA patients. The deduced amino acid sequence showed homology to 60S ribosomal protein L3 (RpL3) of Aspergillus nidulans, Saccharomyces cerevisiae and Homo sapiens. The RpL3 of S. cerevesiae, tcm1, to which TS1 sequence shows significant homology (72% identity), is known to be responsible for conferring resistance against trichodermin (antibiotic, inhibiting protein synthesis). The present study has led to identification, cloning and expression of a 44-kDa novel allergen/antigen of Afu with sequence homology to L3 ribosomal protein with a probable role in resistance of Afu to antifungal drugs. Sixty-four per cent sequence identity of Afu RpL3 with human RpL3 and common regions in their predicted epitopes suggest a possibility of involvement of Afu RpL3 in autoimmune reactions due to molecular mimicry.

Identification of 45 kD antigen in immune complexes of patients of allergic bronchopulmonary aspergillosis.

A glycoprotein antigen with an apparent mw of 45 kD was observed to be predominant in the circulating immune complexes isolated from patients of allergic bronchopulmonary aspergillosis as well as in the immune complexes prepared in vitro. Further characterisation of 45 kD antigen with trypsin showed four immunologically active peptides with mw 43, 36, 33 and 16 kD. Carbohydrate characterization using various lectins (Maackia amurensis agglutinin, Sambucus nigra agglutinin, Peanut agglutinin, Galanthus nivalis agglutinin and Datura stramonium agglutinin) showed presence of both N-linked and O-linked sugar moieties such as mannose, glucose, galactose and N-acetyl glucosamine. Predominant presence of 45 kD antigen in immune complexes, recognition of 45 kD by monoclonal antibodies raised against glycoprotein rich fraction of A. fumigatus and presence of elastinolytic protease activity indicate that 45 kD antigen is probably a potent virulence factor and may be contributing to the pathogenesis of ABPA by its biological as well as immunological activities.

Aspergillus fumigatus specific antibodies in multitransfused children with human immunodeficiency virus (HIV) infection in relation to serum levels of Interleukin-2, gamma Interferon and tumour necrosis factor.

Anti-Aspergillus fumigatus antibodies (IgG and IgE class) and serum levels of cytokines (gamma Interferon, Interleukin-2 and tumour necrosis factor-alpha) were studied in multitransfused (MT) children in relation to human immunodeficiency virus (HIV) infection. The specific antibodies to Aspergillus fumigatus were present in 25 per cent of MT children seropositive for HIV as compared to only 2 per cent among HIV-negative MT children (X2 = 14, P < 0.001). Estimation of serum cytokines level in MT children showed that the asymptomatic HIV-infected children had elevated levels of gamma interferon (Y-IFN) and tumor necrosis factor-alpha (TNF-alpha) without any alteration of Interleukin-2 (IL-2) level, compared to HIV-negative group. However, clinically diagnosed cases of AIDS in the HIV-infected group showed elevation of all the three cytokines levels as compared to HIV negative group, as well as asymptomatic HIV infected group. Presence or absence of concomitant A. fumigatus infection did not lead to alteration of Y-IFN and IL-2 level in the HIV infected group, while TNF-alpha levels were markedly raised in the cases with evidences of presence of A. fumigatus specific antibodies irrespective of whether the group belonged to asymptomatic HIV infection or clinically proven cases of AIDS. The significance of these altered cytokines profile with respect to occurence of A. fumigatus infection in HIV-positive MT children has been discussed.

Binding of pulmonary surfactant proteins A and D to Aspergillus fumigatus conidia enhances phagocytosis and killing by human neutrophils and alveolar macrophages.

To determine whether the lung surfactant proteins A (SP-A) and D (SP-D) are involved in the initial protective immunity against opportunistic pulmonary fungal infections caused by Aspergillus fumigatus, we performed a series of in vitro functional studies to see if SP-A and SP-D enhanced binding, phagocytosis, activation, and killing of A. fumigatus conidia by human alveolar macrophages and circulating neutrophils. Both SP-A and SP-D bound to carbohydrate structures on A. fumigatus conidia in a calcium-dependent manner. SP-A and SP-D were also chemoattractant and significantly enhanced agglutination and binding of conidia to alveolar macrophages and neutrophils. Furthermore, in the presence of SP-A and SP-D, the phagocytosis, oxidative burst, and killing of A. fumigatus conidia by neutrophils were significantly increased. These findings indicate that SP-A and SP-D may have an important immunological role in the early antifungal defense responses in the lung, through inhibiting infectivity of conidia by agglutination and by enhancing uptake and killing of A. fumigatus by phagocytic cells.