Immunization of cattle with recombinant Babesia bovis merozoite surface antigen-1.

Cattle immunized with a recombinant merozoite surface antigen-1 molecule (MSA-1) produced high-titered antibody that reacted with the surface of the parasite and neutralized merozoite infectivity in vitro. However, recombinant MSA-1 immunization did not confer protection against challenge with virulent Babesia bovis. These results indicate that antibody-mediated neutralization of merozoite infectivity in vitro, at least for MSA-1-specific antibody, does not reflect in vivo protective immunity to babesiosis.     

Early Dry Eye Disease Onset in a NOD.H-2h4 Mouse Model of Sjögren's Syndrome

PurposeTo develop a mouse model of human dry eye disease (DED) for investigation of sex differences in autoimmune-associated dry eye pathology.MethodsOcular surface disease was assessed by quantifying corneal epithelial damage with lissamine green stain in the NOD.H-2^h4,IFNγ^−/−,CD28^−/− (NOD.H-2^h4 DKO) mouse model of Sjögren''s syndrome (SS). Lacrimal gland function was assessed by tear volume quantification with phenol red thread and lacrimal gland inflammation (i.e., dacryoadenitis) was assessed by quantification of immune cell foci, flow cytometric analysis of immune cell composition, and expression of proinflammatory markers.ResultsThe NOD.H-2^h4 DKO mouse model of SS exhibits greater age-dependent increases in corneal damage than in NOD.H-2^h4 parental mice and demonstrates an earlier disease onset in females compared to males. The severity of ocular surface disease correlates with loss of goblet cell density, increased conjunctivitis, and dacryoadenitis that is more pronounced in NOD.H-2^h4 DKO than NOD.H-2^h4 mice. B cells dominate lacrimal infiltrates in 16-week-old NOD.H-2^h4 and NOD.H-2^h4 DKO mice, but T helper cells and macrophages are also present. Lacrimal gland expression of proinflammatory genes, including the P2X7 and P2Y₂ purinergic receptors, is greater in NOD.H-2^h4 DKO than NOD.H-2^h4 mice and correlates with dacryoadenitis.ConclusionsOur results demonstrate for the first time that autoimmune dry eye disease occurs in both sexes of NOD.H-2^h4 DKO and NOD.H-2^h4 mice, with earlier onset in female NOD.H-2^h4 DKO mice when compared to males of the same strain. This study demonstrates that both NOD.H-2^h4 and NOD.H-2^h4 DKO mice are novel models that closely resemble SS-related and sex-dependent DED.     

Sarcoidosis following HIV infection: evidence for CD4+ lymphocyte dependence

BACKGROUND: The chronic granulomatous inflammation of sarcoidosis has been hypothesized to depend on the CD4+ T-helper lymphocyte. HIV infection, which depletes these cells, has been reported to attenuate the manifestations of sarcoidosis. STUDY OBJECTIVES: We asked whether the development of symptomatic sarcoidosis in the context of preexisting HIV infection was dependent on the CD4+ lymphocyte count. DESIGN: We performed a retrospective standardized chart review of all patients who developed granulomatous inflammation following HIV infection at an urban academic referral center. MEASUREMENTS: We identified seven patients with sarcoidosis within this cohort and compared their CD4+ lymphocyte count to that in a cohort of 16 patients in whom similar granulomatous inflammation was found but who did not have sarcoidosis. We then compared our cases to all reported cases using a systematic literature review. RESULTS: The CD4+ lymphocyte count was > 200 cells/ microL in all of our patients with HIV infection when they developed subsequent sarcoidosis. In contrast, specific etiologies for granulomatous inflammation were found in all 10 HIV-infected patients who presented with granulomatous inflammation and a CD4+ lymphocyte count of < 200 cells/ microL, with infectious etiologies found in 8 patients. Similarly, there was relative preservation of the CD4+ lymphocyte count in previously reported cases, with 14 of 19 patients (74%) having an absolute CD4+ lymphocyte count of > 200 cells/ microL. CONCLUSIONS: We conclude that the development of the chronic granulomatous inflammation of sarcoidosis appears to depend on the preservation or restoration of the peripheral CD4+ lymphocyte count and that in most cases the CD4+ lymphocyte count exceeds 200 cells/ microL. Furthermore, alternative specific etiologies of granulomatous inflammation are generally identifiable in HIV-infected patients with peripheral CD4+ lymphocyte counts of < 200 cells/ microL.     

Reaching the limits of tuberculosis prevention among foreign-born individuals: a tuberculosis-control program perspective.

Analysis of whether assiduous implementation of American Thoracic Society/Centers for Disease Control and Prevention/Infectious Diseases Society of America guidelines for targeted testing and treatment of latent tuberculosis infection could have prevented any of 223 cases of active tuberculosis in foreign-born persons in San Francisco during the period 2002-2003. We report that 62% of these cases were not preventable and conclude that a further reduction in the incidence of tuberculosis among foreign-born persons will be modest without modification of current guidelines.     

Monoclonal antibody to a conserved epitope on proteins encoded by Babesia bigemina and present on the surface of intact infected erythrocytes.

To define Babesia bigemina-specific antigens on the surface of infected erythrocytes, monoclonal antibodies (MAbs) were identified by live-cell immunofluorescence. As determined by live-cell immunofluorescence, two MAbs made to the Mexico strain reacted with the Mexico strain and three Kenya strains, while three MAbs made to the Kenya-Ngong strain reacted with the Kenya strains but not the Mexico strain. Binding of MAb 44.18 (made to the Mexico strain) to a strain-common epitope was confirmed by immunoelectron microscopy and by surface-specific immunoprecipitation of [35S]methionine-labeled proteins (200, 28, and 16 kDa in size), which also demonstrated that the MAb recognized an epitope on proteins encoded by B. bigemina. In immunoblots, the MAb bound to predominant antigens with sizes of 200 and 220 kDa in erythrocyte lysates infected with strains from Puerto Rico, St. Croix, Texcoco (Mexico), Kenya, and Mexico. Major antigens with sizes of 200 and 220 kDa were isolated from a MAb 44.18 affinity matrix. Calf serum antibodies to these isolated antigens bound to erythrocytes infected with either the Mexico or Kenya strains as determined by live-cell immunofluorescence, allowing the conclusion that at least one conserved surface epitope was recognized. Calf serum antibodies identified major labeled proteins with sizes of 200 and 72 kDa by surface-specific immunoprecipitation, and infected erythrocytes sensitized with these antibodies were phagocytized by cultured bovine peripheral blood monocytes. These results provide a rationale for evaluating antigens identified by MAb 44.18 individually and as components of subunit vaccines.     

Surface epitope localization and gene structure of a Babesia bovis 44-kilodalton variable merozoite surface antigen.

Variation of Babesia bovis merozoite surface antigens occurs among geographic strains of the parasite. In this and a concurrent report, we investigate this variation at the gene and protein level. Using a monoclonal antibody (mAb 23/70.174), B. bovis gene sequences were identified that encoded a surface epitope of a 44-kDa merozoite surface antigen (MSA-2). This epitope is variably expressed among geographic isolates of B. bovis. Here, we describe the MSA-2 protein gene sequence, localize this surface epitope to a repeated amino acid sequence, and investigate the genomic organization of the gene in B. bovis strains from Mexico and Australia. The predicted protein sequence had hydrophobic regions at its amino and carboxy termini consistent with a signal peptide and a membrane anchor via glycosylphosphatidyl inositol, respectively. The surface epitope recognized by mAb 23/70.174 was localized within a 24-amino acid sequence which is repeated twice in tandem. Six different EcoRI bands hybridized to the MSA-2 gene sequence with varying intensities in genomic Southern blots of the homologous strain. Two of these appear to be alleles of the MSA-2 gene. Whereas 5' and 3' sequences of the MSA-2 gene sequence were detected in an Australia strain of B. bovis, internal gene sequences encoding the surface epitope were not. The 3' sequences of the MSA-2 gene also had significant sequence similarity with the MSA-1 gene of the Mexico strain B. bovis and a gene from the previously described BabR locus. These data indicate that the MSA-2 protein gene belongs to the BabR locus which encodes variable merozoite surface antigens.     

A molecular epidemiologic analysis of tuberculosis trends in San Francisco, 1991-1997.

BACKGROUND: To decrease tuberculosis case rates and cases due to recent infection (clustered cases) in San Francisco, California, tuberculosis control measures were intensified beginning in 1991 by focusing on prevention of Mycobacterium tuberculosis transmission and on the use of preventive therapy. OBJECTIVE: To describe trends in rates of tuberculosis cases and clustered cases in San Francisco from 1991 through 1997. DESIGN: Population-based study. SETTING: San Francisco, California. PATIENTS: Persons with tuberculosis diagnosed between 1 January 1991 and 31 December 1997. MEASUREMENTS: DNA fingerprinting was performed. During sequential 1-year intervals, changes in annual case rates per 100,000 persons for all cases, clustered cases (cases with M. tuberculosis isolates having identical fingerprint patterns), and cases in specific subgroups with high rates of clustering (persons born in the United States and HIV-infected persons) were examined. RESULTS: Annual tuberculosis case rates peaked at 51.2 cases per 100,000 persons in 1992 and decreased significantly thereafter to 29.8 cases per 100,000 persons in 1997 (P < 0.001). The rate of clustered cases decreased significantly over time in the entire study sample (from 10.4 cases per 100,000 persons in 1991 to 3.8 cases per 100,000 persons in 1997 [P < 0.001]), in persons born in the United States (P < 0.001), and in HIV-infected persons (P = 0.003). CONCLUSIONS: The rates of tuberculosis cases and clustered tuberculosis cases decreased both overall and among persons in high-risk groups. This occurred in a period during which tuberculosis control measures were intensified.