Excited to share our work by @BenIsraelow et al published today. We asked what are the roles of antibodies vs. T cells in controlling primary infection, reinfection, and vaccine-mediated protection? (1/n)
First, we asked if B cells are needed to control primary infection. We used muMT mice (devoid of B cells) transduced with AAV-hACE2. These mice had only a slight delay in viral clearance. Thus B cells are not necessary for controlling primary SARS-CoV-2 infection. (2/n)
However, in mice that have neither T cells nor B cells (RAG-/-), SARS-CoV-2 persisted with no sign of clearance. Thus, innate immunity is insufficient, and adaptive immunity is required to control primary infection. (3/n)
These findings have important implications in the persistent SARS-CoV-2 infection we see in immunocompromised patients, and imply that defects in T and B cell immunity predispose people for chronic COVID infection. (4/n)
Next, we wanted to know if CD4 vs. CD8 T cells are required for clearance of primary SARS-CoV-2 infection. Depletion of CD4 or CD8 had moderate effects on loss of viral control. However, depletion of both CD4 and CD8 T cells resulted enhanced viral replication. (5/n)
What is the role of CD4 T cells in primary SARS-CoV-2 clearance? It turns out that the role of CD4 T cells is mainly to support antibody production (panel D), because in the absence of B cells (panel C), CD4 depletion had little impact on viral control. (6/n)
Are T cells or Ab sufficient to control primary infection with SARS-CoV-2? @BenIsraelow collected either sera (Ab) or T cells from infected mice at 14 days, and transfer to RAG-/- host, which were challenged with virus. Turns out that Ab > T cells in controlling virus. (7/n)
Next, we asked whether mRNA vax or natural SARS-CoV-2 infection establishes lung-resident CD8 T cells. While both induced comparable circulating CD8 T cells (IV+), natural infection >> vax in establishing tissue-resident CD8 T cells (IV-). #mucosalimmunity (8/n)
How well does the mRNA vax or primary infection protect against VOC, and how much of that depends on CD8 T cells? Great news is that the mRNA vax or prior infection protected 100% of mice, even after CD8 T depletion at the time of challenge. (9/n)
In the lungs of these mice, we found that both mRNA vax mice and convalescent mice were completely protected from disease with original strain (WA1) and the B.1.351 virus. Even without CD8 T, all vax & convalescent mice eliminated infectious virus (G).(10/n)
Further, by immunizing with varying doses of the mRNA vax, @BenIsraelow found a strong correlation between anti-spike IgG levels, neutralizing Ab and protection against COVID-19 disease. (11/n)
In conclusion, while T cells were sufficient for the clearance of primary infection, they were not required for protection against reinfection or vaccine-mediated protection. (12/n)
We did not test the sufficiency of T cells in vaccine-mediated protection. However, a very nice study by @Masopust_Vezys shows the promise of adding T cell antigens to vaccines. (13/n)
While we did not test the Delta variant, with its high viral load and transmission capacity, vaccines that induce mucosal immunity (TRM, IgA) may become important to better prevent infection and transmission. (14/n)
Sharing this scoping review on "Post-Acute sequelae of COVID-19 in pediatric patients within the United States" by @ChrisMillerDO - an amazing @YalePediatrics infectious diseases fellow focused on research and treatment of #longcovidkids (1/)
Key findings:
- Most pediatric LC patients were adolescents.
- ♀>♂️
- 80% of pediatric LC patients started with a mild initial infection.
- Asthma, atopy, allergic rhinitis (type 2 immune diseases), and obesity were frequently reported pre-existing conditions. (2/)
The most frequently reported symptoms in #longcovidkids are listed here (3/)
An important study by F. Eun-Hyung Lee's team shows that long lived plasma cells (the source of long-term circulating antibodies) fail to establish after mRNA vaccination (even combined with SARS-CoV-2 infection). 🧵 (1/) nature.com/articles/s4159…
The longevity of antibody-mediated protection against infectious diseases rely on whether or not the vaccines can establish long lived plasma cells (LLPC) in the bone marrow. They are the source of circulating antibodies for years to decades. (2/) nature.com/articles/s4159…
The study by Nguyen et al examined the long lived and short lived plasma cells in the bone marrow in people who received COVID mRNA vaccines, tetanus and flu vaccines at various time points . They found no LLPC (PopD) specific to COVID but found PopD against tetanus and flu. (3/)
A new study led by @marioph13 in collaboration with the @WilenLab examines two bat coronaviruses that are the closest relatives of SARS-CoV-2 for their ability to infect, evade immunity and transmit between rodents. Some key takeaway points 🧵 (1/) nature.com/articles/s4156…
Here is a link to the accessible manuscript (2/) rdcu.be/dPjsA
We used the highest biosafety level available at Yale (BSL3+) to conduct the study and we did not introduce gain-of-function mutations into the bat viruses. No serial passaging of the viruses were done - to avoid adaptation. Grateful to @YaleEHS for all the support. (3/)
Sharing our new study by @keylas3, @SilvaJ_C, Rafael Bayarri Olmos et al (with T. Horvath & @PutrinoLab) showing that a passive transfer of IgG from patients with #longCOVID into mice recapitulates ⬆️ pain and other symptoms 🧵 (1/)
Long COVID disease pathogenesis includes persistent SARS-CoV-2 virus, dysbiosis, herpesvirus reactivation, autoimmunity, and others. In this study, we focus on the role of autoantibodies. (2/)
Among the original Mount Sinai-Yale Long COVID study participants 👇🏼 (with @PutrinoLab), we focused on patients with high neurological symptom burden (n=55), and compared antibodies with convalescent controls (n=42) or uninfected controls (n=39). (3/) nature.com/articles/s4158…
What determines whether someone gets infected or not after exposure to SARS-CoV-2? A new study by Lindeboom et al examined this question with COVID-19 human challenge study. @BenIsraelow and I summarize their key findings in this News & Views 🧵 (1/) nature.com/articles/d4158…
The study: 16 healthy young volunteers with no prior infection or vaccination were inoculated nasally with a low dose of pre-Alpha SARS-CoV-2 strain. Interestingly, only 6 had sustained infection, 3 had transient, and 7 had abortive infection at this dose. (2/) nature.com/articles/s4158…
The three infection outcomes allowed investigation of key features associated with susceptibility vs. resistance. Higher baseline expression of HLA-QA2 mRNA was associated with COVID resistance. Early nasal interferon I response was seen in those with transient infection. (3/)
Preventing infection is the best way to avoid diseases like #PAIS. A new study from our team @tianyangmao, Jooyoung Kim, @marioph13 et al shows that a generic antibiotic neomycin acts on the host immune system in the👃🏽to trigger antiviral resistance. (1/)🧵 pnas.org/doi/10.1073/pn…
This work is inspired by @SmitaGopinath et al who showed that an antibiotic class called aminoglycosides has an unusual antiviral property. Aminoglycosides including neomycin trigger interferon-stimulated genes through a TLR3-dependent mechanism. (2/) ncbi.nlm.nih.gov/pmc/articles/P…
In our current study, we showed that nasal application of neomycin in mice one day before infection reduces viral load and disease burden after the SARS-COV-2 challenge. @tianyangmao (3/)