Publications by authors named "Olga L Fernandez"

Unlabelled: Macrophages are the principal host cells of . in human infection and play a critical role in controlling infection and enabling parasite survival and persistence. Nevertheless, understanding of drug resistance in leishmaniasis has primarily focused on the parasite.

View Article and Find Full Text PDF
Article Synopsis
  • Interleukin-2 (IL-2) has been used for cancer treatment for over 30 years, but high toxicity has led to the development of mutant variants with lower toxicity and enhanced therapeutic benefits.
  • The Center of Molecular Immunology has created a new variant called IL-2 no-alpha mutein, which is currently undergoing a Phase I/II clinical trial and is produced in E. coli through a process that requires refolding.
  • A new purification method involving copper-catalyzed air oxidation ensures proper disulfide bond formation, resulting in a protein with improved 3D structure, higher purity, and greater biological activity compared to previous methods.
View Article and Find Full Text PDF

Objective: Arboviruses pose a challenge in ensuring the supply of pathogen-free blood components because they are not routinely screened in blood banks, and blood components from infected asymptomatic donors could be transfused. This study aimed to detect and characterize arboviral infections in Colombian blood donors.

Methods: In a cross-sectional study, the prevalence of dengue (DENV), Zika (ZIKV), and chikungunya (CHIKV) viruses and co-infections of blood donors were compared between an epidemic period (November 2019-February 2020,  = 462) and an endemic period (November 2021-August 2022,  = 1,119).

View Article and Find Full Text PDF
Article Synopsis
  • - Neutrophils play a crucial role in fighting infections, but their function in drug-resistant infections, like leishmaniasis, is not well understood.
  • - Research shows that drug-resistant parasites change the expression of certain neutrophil genes, increasing detoxification processes and reducing cytokine production, particularly impacting a chemokine called CCL3.
  • - Reduced CCL3 levels hinder neutrophils’ ability to recruit other immune cells, which was confirmed in mouse models, highlighting how drug-resistant parasites can alter immune responses in infected skin.
View Article and Find Full Text PDF
Article Synopsis
  • *2! It finds that parasite survival rates in various cell models can predict treatment success, with Sb-resistant strains being associated with higher odds of treatment failure and larger lesion sizes in mouse models.
  • *3! Host risk factors also complicate the interpretation of treatment outcomes, indicating that both parasite characteristics and patient conditions play critical roles in the effectiveness of leishmaniasis treatment.
View Article and Find Full Text PDF

The endosymbiotic Leishmania RNA virus 1 (LRV1) has been associated with severity and clinical manifestations of American tegumentary leishmaniasis caused by species of the Leishmania (Viannia) subgenus. Between and within Leishmania species, and among endemic countries, the prevalence of LRV is highly variable. The LRV virus has not been detected in L.

View Article and Find Full Text PDF
Article Synopsis
  • Antimonial drugs and miltefosine often fail to effectively treat cutaneous leishmaniasis, prompting research into alternative oral combination therapies to boost treatment efficacy and prevent drug resistance.
  • In a study, posaconazole and itraconazole showed high potency against various Leishmania (Viannia) panamensis strains, while fluconazole and voriconazole were less effective.
  • The combination of miltefosine and posaconazole demonstrated significant synergy, leading to a greater reduction in infection when tested against clinical strains, indicating its potential as a new treatment strategy.
View Article and Find Full Text PDF
Article Synopsis
  • Recent research shows that the body's natural immune response may play a role in how well antimicrobial drugs work, particularly against leishmaniasis.
  • The study focused on how clinical strains of parasites resistant to a common antileishmanial drug, pentavalent antimony (SbV), affect neutrophil activation by comparing sensitive and resistant strains.
  • The findings indicate that neutrophils infected with drug-resistant strains produce less reactive oxygen species and have a different expression profile for specific activation markers compared to those infected with drug-sensitive strains.
View Article and Find Full Text PDF

is the main causative agent of cutaneous leishmaniasis in Colombia and is usually treated with either meglumine antimoniate (MA) or miltefosine (MIL). In recent years, there has been increasing evidence of the emergence of drug-resistance against these compounds. Neutrophils are known to play an important role in immunity against .

View Article and Find Full Text PDF

Infection by () , the predominant etiologic agent for cutaneous leishmaniasis in Colombia, is characterized by a chronic mixed inflammatory response. Current treatment options are plagued by toxicity, lengthy treatment regimens, and growing evidence of drug resistance. Immunotherapy, modulating the immune system to mount a protective response, may provide an alternate therapeutic approach.

View Article and Find Full Text PDF

Cutaneous and mucosal leishmaniasis is widely distributed in Central and South America. Leishmania of the Viannia subgenus are the most frequent species infecting humans. L.

View Article and Find Full Text PDF

Background: Therapeutic response in infectious disease involves host as well as microbial determinants. Because the immune and inflammatory response to Leishmania (Viannia) species defines the outcome of infection and efficacy of treatment, immunomodulation is considered a promising therapeutic strategy. However, since Leishmania infection and antileishmanial drugs can themselves modulate drug transport, metabolism and/or immune responses, immunotherapeutic approaches require integrated assessment of host and parasite responses.

View Article and Find Full Text PDF

Background: Pentavalent antimonials have been the first line treatment for dermal leishmaniasis in Colombia for over 30 years. Miltefosine is administered as second line treatment since 2005. The susceptibility of circulating populations of Leishmania to these drugs is unknown despite clinical evidence supporting the emergence of resistance.

View Article and Find Full Text PDF

Treatment failure and parasite drug susceptibility in dermal leishmaniasis caused by Leishmania (Viannia) species are poorly understood. Prospective evaluation of drug susceptibility of strains isolated from individual patients before drug exposure and at clinical failure allows intrinsic and acquired differences in susceptibility to be discerned and analyzed. To determine whether intrinsic susceptibility or loss of susceptibility to miltefosine contributed to treatment failure, we evaluated the miltefosine susceptibility of intracellular amastigotes and promastigotes of six Leishmania (Viannia) braziliensis and six Leishmania (Viannia) panamensis strains isolated sequentially, at diagnosis and treatment failure, from two children and four adults ≥55 years old with concurrent conditions.

View Article and Find Full Text PDF

We assessed the safety, tolerability, and immunogenicity of a mixture of three synthetic peptides derived from the Plasmodium vivax circumsporozoite protein formulated in Montanide ISA 720 or Montanide ISA 51. Forty healthy malaria-naive volunteers were allocated to five experimental groups (A-E): four groups (A-D) were immunized intramuscularly with 50 and 100 μg/dose injections of a mixture of N, R, and C peptides formulated in the two different adjuvants at 0, 2, and 4 months and one group was administered placebo. Vaccines were immunogenic, safe, well tolerated, and no serious adverse events related to the vaccine occurred.

View Article and Find Full Text PDF

Substantial experimental evidence indicates that the Plasmodium circumsporozoite (CS) protein has great potential as a vaccine candidate. We tested the safety and immunogenicity of vaccines composed of P. vivax CS-derived synthetic peptides.

View Article and Find Full Text PDF