Determinación de la prevalencia de Dirofilaria immitis, mediante la Prueba Rápida de Inmunocromatografía en perros del municipio de puerto barrios, Izabal, en el año 2016

La Dirofilariasis, es una infección causada por Dirofilaria immitis que afecta el corazón del perro, y menos frecuente en el gato. Es una enfermedad que utiliza a los mosquitos de los géneros Aedes, Anopheles y Culex , y es así como se disemina la enfermedad. Además, puede llegar a infectar al humano de una forma accidental. Se realizó un estudio en el municipio de Puerto Barrios, Izabal, con el objetivo de establecer la prevalencia de perros seropositivos y contribuir con el estudio epidemiológico de D. immitis¸ en Guatemala. Para este estudio transversal descriptivo, se muestrearon 80 caninos completamente al azar. En el estudio se incluyeron caninos machos y hembras, mayores de un año de edad, sin previo tratamiento a ivermectina. Se tomó una muestra de sangre periférica de la vena cefálica o safena, de cada uno. Cada una de las muestras fue sometida a la de prueba inmunocromatografía rápida (Uranotest Dirofilaria®,) para determinar la presencia de antígenos de D. immitis. En el estudio, no se encontró la presencia de antígenos circulantes en los perros muestreados, por lo tanto la prevalencia fue de cero. Sin embargo, este hallazgo no descarta la presencia del parásito en el municipio de Puerto Barrios, Izabal. Debido al resultado obtenido fue establecer alguna relación entre sexo, edad, raza y procedencia con la seropositividad

Normal blood cell counts in peripheral blood and normal CXCL12 levels in serum indicate proper CXCL12/CXCR4 signaling in HuCXCR4KI mice.

<p>Each symbol represents the result from an individual mouse. <b>A</b>, Flow cytometric analysis of total leukocyte (WBCs) and leukocyte subset counts in peripheral blood of HuCXCR4KI and WT control littermate mice. Cell counts were estimated with absolute counting beads, as described in the methods section. WBCs were defined as CD45⁺ blood cells. WBC subsets were defined based on cell surface marker expression, as follows: monocytes (CD45⁺CD11b⁺CD115⁺Ly6G^-), neutrophils (CD45⁺CD11b⁺CD115^-Ly6G⁺), T cells (CD45⁺CD11b^-Thy1.2⁺), B cells (CD45⁺CD11b^-CD19⁺), NK cells (CD45⁺CD11b^-CD49b⁺). <b>B</b>, Detection by ELISA of CXCL12 levels in the serum of HuCXCR4KI and WT control littermate mice; n.s. = non-significant (unpaired Student’s <i>t</i>-test).</p

Survey of human CXCR4 expression in TMA of human specimens of normal appearance and in corresponding tissues of homozygous HuCXCR4KI mice.

<p>Survey of human CXCR4 expression in TMA of human specimens of normal appearance and in corresponding tissues of homozygous HuCXCR4KI mice.</p

Human CXCR4 knock-in design and confirmation of human CXCR4 expression in peripheral blood cells of heterozygous (HuCXCR4KI/WT) and homozygous (HuCXCR4KI) mice.

<p><b>A</b>, Schematic of genetic targeting strategy for knock-in of full length human CXCR4 coding region. <b>B</b>, Flow cytometric analysis of peripheral blood leukocytes from littermate mice with antibodies specific for human CXCR4.</p

Expression of human CXCR4 mRNA is detectable in various organs of HuCXCR4KI mice.

<p>Relative expression levels of human CXCR4 mRNA in whole organs of HuCXCR4KI male mice, as detected by RT-qPCR (Taqman). Equal amounts of total RNA were retro-transcribed and the levels of mouse Rpl19 transcript were used as a normalization control.</p

Improved Lysosomal Trafficking Can Modulate the Potency of Antibody Drug Conjugates

Antibody drug conjugates (ADCs) provide an efficacious and relatively safe means by which chemotherapeutic agents can be specifically targeted to cancer cells. In addition to the selection of antibody targets, ADCs offer a modular design that allows selection of ADC characteristics through the choice of linker chemistries, toxins, and conjugation sites. Many studies have indicated that release of toxins bound to antibodies via noncleavable linker chemistries relies on the internalization and intracellular trafficking of the ADC. While this can make noncleavable ADCs more stable in the serum, it can also result in lower efficacy when their respective targets are not internalized efficiently or are recycled back to the cell surface following internalization. Here, we show that a lysosomally targeted ADC against the protein APLP2 mediates cell killing, both in vitro and in vivo, more effectively than an ADC against Trop2, a protein with less efficient lysosomal targeting. We also engineered a bispecific ADC with one arm targeting HER2 for the purpose of directing the ADC to tumors, and the other arm targeting APLP2, whose purpose is to direct the ADC to lysosomes for toxin release. This proof-of-concept bispecific ADC demonstrates that this technology can be used to shift the intracellular trafficking of a constitutively recycled target by directing one arm of the antibody against a lysosomally delivered protein. Our data also show limitations of this approach and potential future directions for development

Site-Dependent Degradation of a Non-Cleavable Auristatin-Based Linker-Payload in Rodent Plasma and Its Effect on ADC Efficacy

<div><p>The efficacy of an antibody-drug conjugate (ADC) is dependent on the properties of its linker-payload which must remain stable while in systemic circulation but undergo efficient processing upon internalization into target cells. Here, we examine the stability of a non-cleavable Amino-PEG6-based linker bearing the monomethyl auristatin D (MMAD) payload site-specifically conjugated at multiple positions on an antibody. Enzymatic conjugation with transglutaminase allows us to create a stable amide linkage that remains intact across all tested conjugation sites on the antibody, and provides us with an opportunity to examine the stability of the auristatin payload itself. We report a position-dependent degradation of the C terminus of MMAD in rodent plasma that has a detrimental effect on its potency. The MMAD cleavage can be eliminated by either modifying the C terminus of the toxin, or by selection of conjugation site. Both approaches result in improved stability and potency <i>in vitro</i> and <i>in vivo</i>. Furthermore, we show that the MMAD metabolism in mouse plasma is likely mediated by a serine-based hydrolase, appears much less pronounced in rat, and was not detected in cynomolgus monkey or human plasma. Clarifying these species differences and controlling toxin degradation to optimize ADC stability in rodents is essential to make the best ADC selection from preclinical models. The data presented here demonstrate that site selection and toxin susceptibility to mouse plasma degradation are important considerations in the design of non-cleavable ADCs, and further highlight the benefits of site-specific conjugation methods.</p></div

Additional file 3: Figure S3. of Targeting the CXCR4 pathway using a novel anti-CXCR4 IgG1 antibody (PF-06747143) in chronic lymphocytic leukemia

The PF-06747143 parent IgG1 antibody (m15 IgG1) induces cell death and this activity is similar in HR and LR CLL patients. Primary CLL-B cells derived from CLL patients were incubated either alone (n = 10) or co-cultured with stroma-NK-tert cells (n = 10) and treated with vehicle, IgG1 control Ab, or m15-IgG1 antibody for 48 h. Cell death was measured using CD19/CD5/Annexin V staining followed by flow cytometry analysis. The data is derived from five high-risk (HR) and five low-risk (LR) CLL patients. The HR patients are presented with solid symbols (•) and LR patients denoted with hollow symbols (○). The individual data points for each group are shown. The horizontal lines represent the mean for each group Statistical comparisons were performed using Bonferroni’s correction test. (PDF 744 kb