Liana Relina

Gene therapy is still an investigational technique. Viruses are commonly used as vectors to deliver a needed gene to a host (defective) cell. An ideal viral vector is supposed to be genetically stable, non-toxic, and non-immunogenic, to have a high packaging capacity along with other important features. 

What is a Mesenchymal Stem Cell? What Can it Do?

Mesenchymal stem cells (MSCs) are multipotent stem/progenitor cells that are present in different tissues, including the umbilical cord, bone marrow, and fat tissue. MSCs can self-renew by dividing and differentiate into cells of bone, cartilage, muscle and fat cells, and connective tissue. They are also famous for their ability to produce useful growth factors and cytokines. MSCs secrete multiple factors, including prostaglandin E2, interleukin-10, interleukin-1 receptor antagonist, interleukin (IL)-6, leukocyte inhibitory factor, nitric oxide, TNFα stimulated gene 6 (TSG-6), and many others, which limit immune response. In addition, MSCs skew maturing immune cell populations, i.e. populations of regulatory and anti-inflammatory T cells and dendritic cells become more abundant, while pro-inflammatory T cells, dendritic cells, and natural killers (NKs) decrease in numbers.  

Due to these unique features, MSCs are considered a promising approach to treat autoimmune diseases and to manage the rejection of grafts. For over 10 years, they have been successfully used in the therapy of autoimmune diseases (rheumatoid arthritis, ulcerative colitis, type 1 diabetes, multiple sclerosis) and for the inhibition of transplanted organs rejection.

Antisense oligonucleotides (ASOs) are short (about 12 to 25 nucleotides long), synthetic single strands of DNA or RNA that are complementary to a chosen sequence. They can alter RNA and reduce, restore, or modify protein expression. ASOs interact with proteins on the surface of cells and enter the cytoplasm. Then they can work either in right in the cytoplasm or enter the nucleus.

In their naked form, ASOs cannot permeate the plasma membrane and are highly sensitive to degradation by endonucleases and exonucleases. To overcome these problems, ASOs have been chemically modified. On the basis of these modifications, ASOs can be broadly classified into three generations.

Common vaccines are synonymous with injections and grant you systemic immunity. But the injection isn’t the only way to develop immunity. And considering how most pathogens, including coronaviruses, get into our bodies, injections might not even be the best way.

SARS-CoV-2 often enters through the nose, where it encounters a specific protein, ACE2, which is found in abundance in the nasal passage. ACE2 is the virus’s doorway into our cells. In fact, the mucosal membrane that lines your airways is often the frontier of your body to face SARS-CoV-2. Immune cells reside underneath your mucosal membranes, creating a front line of defense against invaders and preventing infection from taking root. Your mucosal immune cells produce a special class of antibodies, immunoglobulin A (IgA), that are constantly secreted from the mucosae to protect the nose, gut, and other vulnerable sites from pathogens we’ve seen in the past. This is the mucosal immune system and it is hard to study. Secreted IgA is tricky to measure. “It is a lot easier to measure things from the blood than it is to measure from mucosa,” says Michael Barry, who has developed an experimental intranasal vaccine for COVID-19 at the Mayo Clinic. To determine how much IgA an animal has produced after vaccination typically requires killing the animal to wash IgA off its lungs. In humans, IgA can be measured by collecting nasal fluid or saliva, but the IgA levels will vary depending on how the sample is collected.