How did the adoption of wP-pentavalent affect the global paediatric vaccine coverage rate? A multicountry panel data analysis.

OBJECTIVES: Several studies have highlighted the effects of combination vaccines on immunisation coverage at the national or subnational level. This study examined the effects globally. Worldwide introduction of whole-cell pertussis pentavalent (wP-pentavalent) allowed estimation of incremental coverage effects of combination vaccines on the third doses of diphtheria, tetanus, pertussis (DTP3); hepatitis B (HepB3) and Haemophilus influenzae type B (Hib3). DESIGN: Multicountry panel data analysis. DATA SOURCES: Country-level vaccine coverage data of WHO/UNICEF for the years 1980-2018. METHODS: Linear mixed models were used to estimate the effects of wP-pentavalent introduction by incorporating proxy variables to control for time trend and other time-dependent changes in the immunisation programmes. RESULTS: Introduction of combination vaccines may have improved the coverage of DTP3 by 3percentage points(95% CI 2.5% to 3.6%) globally compared with the coverage in the pre-combination vaccine era. The comparison of coverage rates of HepB3 and Hib3 in before and after wP-pentavalent periods indicates that the introduction of combination vaccines improved the coverage by 10.1 percentage points (95% CI 8.4% to 11.7%) for HepB3 and 9.9 (95% CI 7.1% to 12.7%) for Hib3 in countries that introduced those antigens prior to adoption of wP-pentavalent. Even though the incremental coverage increase of DTP3 appears quite modest, it is still a significant result, especially because DTP vaccine has been in the national immunisation programmes of all countries for about 24 years prior to the introduction of wP-pentavalent. Additionally, the introduction of pentavalent also allowed inclusion of Hib and HepB in the vaccine schedule for a large number of countries (85 and 37, respectively, of the 102 countries included in our analysis). CONCLUSION: The findings suggest that development of combination vaccines with additional antigens is likely to help sustain and improve coverage of existing as well as new childhood vaccines.

Mammalian cellular culture models of Trypanosoma cruzi infection: a review of the published literature.

Cellular culture infection with Trypanosoma cruzi is a tool used to dissect the biological mechanisms behind Chagas disease as well as to screen potential trypanocidal compounds. Data on these models are highly heterogeneous, which represents a challenge when attempting to compare different studies. The purpose of this review is to provide an overview of the cell culture infectivity assays performed to date. Scientific journal databases were searched for articles in which cultured cells were infected with any Trypanosoma cruzi strain or isolate regardless of the study's goal. From these articles the cell type, parasite genotype, culture conditions and infectivity results were extracted. This review represents an initial step toward the unification of infectivity model data. Important differences were detected when comparing the pathophysiology of Chagas disease with the experimental conditions used in the analyzed studies. While Trypanosoma cruzi preferentially infects stromal cells in vivo, most of the assays employ epithelial cell lines. Furthermore, the most commonly used parasite strain (Tulahuen-TcVI) is associated with chagasic cardiomyopathy only in the Southern Cone of South America. Suggestions to overcome these discrepancies include the use of stromal cell lines and parasite genotypes associated with the known characteristics of the natural history of Chagas disease.

A human astrocytoma cell line is highly susceptible to infection with Trypanosoma cruzi.

Astrocytes play a vital role in neuronal protection, homeostasis, vascular interchange and the local immune response. Some viruses and parasites can cross the blood-brain barrier and infect glia. Trypanosoma cruzi, the aetiological agent of Chagas disease, can seriously compromise the central nervous system, mainly in immune-suppressed individuals, but also during the acute phase of the infection. In this report, the infective capacity of T. cruzi in a human astrocyte tumour-derived cell line was studied. Astrocytes exposed to trypomastigotes (1:10 ratio) produced intracellular amastigotes and new trypomastigotes emerged by day 4 post-infection (p.i.). At day 6 p.i., 93% of the cells were infected. Using flow cytometry, changes were observed in both the expression of major histocompatibility complex class I and II molecules and the chemokine secretion pattern of astrocytes exposed to the parasite. Blocking the low-density lipoprotein receptor on astrocytes did not reduce parasite intracellular infection. Thus, T. cruzi can infect astrocytes and modulate the immune response during central nervous system infection.

A human astrocytoma cell line is highly susceptible to infection with Trypanosoma cruzi

Astrocytes play a vital role in neuronal protection, homeostasis, vascular interchange and the local immune response. Some viruses and parasites can cross the blood-brain barrier and infect glia. Trypanosoma cruzi, the aetiological agent of Chagas disease, can seriously compromise the central nervous system, mainly in immune-suppressed individuals, but also during the acute phase of the infection. In this report, the infective capacity of T. cruzi in a human astrocyte tumour-derived cell line was studied. Astrocytes exposed to trypomastigotes (1:10 ratio) produced intracellular amastigotes and new trypomastigotes emerged by day 4 post-infection (p.i.). At day 6 p.i., 93% of the cells were infected. Using flow cytometry, changes were observed in both the expression of major histocompatibility complex class I and II molecules and the chemokine secretion pattern of astrocytes exposed to the parasite. Blocking the low-density lipoprotein receptor on astrocytes did not reduce parasite intracellular infection. Thus, T. cruzi can infect astrocytes and modulate the immune response during central nervous system infection.

[Flow cytometry model for the detection of neutralizing antibodies against of IFN-ß]. / Modelo de detección de anticuerpos neutralizantes contra IFN-ß mediante citometría de flujo.

INTRODUCTION: Interferon beta (IFN-ß) is a treatment for relapsing remitting multiple sclerosis. However, the therapeutic use of recombinant proteins induces a humoral immunologic response resulting in the induction of binding (BAb) or neutralizing (NAb) antibodies against the biological product. The presence of neutralizing antibodies has been associated with decreased IFN-ß treatment efficacy. MATERIALS AND METHODS: Two tumor cell lines (K562 and U937) were cultivated with human recombinant IFN-ß1a at different concentrations and lengths of time in order to measure the expression of intracellular ISG15, an inducible molecule in the IFN-ß1a signaling cascade. Blood was obtained from non-immunized and IFN-ß1a immunized (100,000 IU) New Zealand rabbits. The presence of BAb was evaluated by ELISA. For NAb detection, sera 1:20 dilution were added to the IFN-ß1a-stimulated cell lines, and ISG15 expression was evaluated by flow cytometry. RESULTS: K562 cells provided the better cell line for the assay, stimulated with a dose of 1,000 IU of IFN-ß1a, and a 1:100 dilution for the primary antibody and a 1:200 dilution for the secondary antibody. ISG15 expression was compared between cells alone or cultivated with IFN-ß1a. Mean fluorescence intensity (MFI) for ISG-15 expression median was 198 arbitrary units (AU) with interquartile ranges of 173-231 AU for non-stimulated cells and 430 AU with interquartile ranges of 316-611.5 AU for IFN-ß1a stimulated cells (p<0.01). Immunized rabbit sera decreased the expression of ISG-15 in K562 cells stimulated with IFN-ß1a, whereas non-immunized rabbit sera did not. CONCLUSIONS: This rabbit model demonstrates that ISG15 expression evaluated with flow cytometry can be used as a detection assay for NAb.