So excited to be a part of this important study led by @michelle_monje on how significant longterm neurologic damage can occur after a mild respiratory-only SARS-CoV-2 infection. My own🧵on the findings of this study with relevance to #longCovid (1/)
How can a mild respiratory SARS-CoV-2 infection lead to longterm neurological symptoms? Possibilities include 1) direct infection of 🧠, 2) autoimmunity, and 3) inflammatory impact of infection distal to the 🧠. In this study, we focused on 3) 👇🏽 (2/)
To achieve this goal, @peowenlu & @ericsongg used a mouse model developed by @BenIsraelow & @ericsongg in which we can control where the infection happens. Using AAV-hACE2 intratracheally, we can confine the SARS-CoV-2 infection only to the lungs. (3/)
In fact, mice infected only in the respiratory tract show no evidence for weight loss (a disease measurement)(B),and no evidence of SARS-CoV-2 infection in the brain (C). (4/)
So what do systemic (serum) and local (cerebrospinal fluid; CSF) cytokines look like after this mild respiratory-only infection? Not surprisingly, we see many elevated cytokines 7 days after infection in the serum. We also see elevated cytokines in the CSF. (5/)
Somewhat unexpectedly, we also see that some of these cytokines remain elevated at 7 weeks post infection in both sera and CSF. Similarly elevated cytokines have been reported from the sera of long COVID patients by others, months after primary infection. (6/)
What does a respiratory-only mild COVID do to the brain? @ThisIsAnthonyFC and @AnnaGeraghty2 examined the subcortical white matter of two independent strains of mice and found consistently increased microglial reactivity at 7 days and 7 weeks post infection. (7/)
Next, with @nathavindra, autopsies from 9 individuals found to be SARS-CoV-2-positive by nasal swab PCR at the time of death were examined. Brains from those with even mild or asymptomatic SARS-CoV-2 infection had microglial reactivity in subcortical white matter. (8/)
Neurogenesis in the hippocampus is thought to support memory function. Reactive microglia can impair this process. Indeed, mice that had mild SARS-CoV-2 infection 7 days or 7 weeks prior had significantly lower # of neuroblasts than controls. This could ⬇️ memory function. (9/)
What can lead to impaired neurogenesis in hippocampus? We looked into a chemokine called CCL11 (eotaxin-1) which was shown to reduce neurogenesis (Villeda et al). In our mice, CCL11 was elevated in the CSF 7 weeks after mild respiratory infection. (10/)
What other changes are happening in the brain of mice with mild respiratory infection? Within just 7 days of infection, we found a loss of ~1/3 of oligodendrocytes, which persisted for at least 7 weeks! Analysis by @ThisIsAnthonyFC and @AnnaGeraghty2 (12/)
This loss of oligodendrocytes was accompanied by reduced myelinated axon density in subcortical white matter within 7 days of infection. This could lead to ⬇️ neural circuit function, axon health and to numerous deleterious neurological consequences of SARS-CoV-2 infection. (13/)
In a nutshell, this study illustrates that respiratory-only mild SARS-CoV-2 infection can lead to detrimental changes in the brain, likely mediated by inflammatory factors. Similar neuropathobiology may be shared in chemo-brain, post-ICU syndrome and ME/CFS. (15/)
This study also opens up all kinds of questions and possibilities. For example, therapies that can 1) block inflammatory cytokines, 2) block inducers of such cytokines, or 3) reset reactive microglia can be considered for future clinical trials. Thank you for reading till end.
I highly recommend this very informative thread posted by @michelle_monje on this study.
Introducing BEACON (Bioactive Enhanced Adjuvant Chemokine Oligonucleotide Nanoparticles) to stimulate mucosal immune responses against genital #HSV infection. Awesome work led by @sachinbhag, who designed and developed BEACON to guide T and B cells (1/) biorxiv.org/content/10.110…
The BEACON nanoparticle is composed of CpG ODN (TLR9 agonist) and CXCL9 (chemokine). When applied to the vaginal mucosa, the recruitment of antiviral T cells is achieved with minimal local inflammation - much more potent than CpG or CXCL9 separately. (2/)
Intramuscular vaccines do not promote mucosal immunity. BEACON can be used as a local adjuvant to boost HSV-2 gD- or gB-specific T and B cells, preventing not only disease/death but also blocking viral load in both vaginal tissue and dorsal root ganglia (🚫latency)(3/)👇🏼
A fascinating new study by Vishnu Shankar et al. @stanfordimmuno shows that oxidative stress is a shared characteristic of ME/CFS and Long COVID in lymphocytes due to inability to clear reactive oxygen species. This happens in sex-specific manner. (1/) pnas.org/doi/abs/10.107…
Females show higher mtROS levels and insufficient antioxidant levels, while males show mitochondrial lipid oxidative damage. While the reason for this is unclear, it may explain the sex differences in lymphocyte dysfunction we see in PAIS in general. (2/) science.org/doi/10.1126/sc…
ROS-targeting therapies were tested. Metformin treatment in vitro showed some impact on CD4 T cell proliferation. I suspect that other therapies to induce autophagy/mitophagy might also benefit restoration of T cell phenotype. #LowDoseRapamycin 👇🏼 (3/) polybio.org/projects/long-…
Published today! Victoria Bastos, @KerrieGreene_ et al found two distinct immunotypes of ME/CFS based on the cerebrospinal fluid analysis. Great collaboration with @MBVanElzakker @microbeminded2 and the Bragée clinic in Sweden. (1/) academic.oup.com/jimmunol/artic…
This is perfect timing as Victoria will present these data at the @polybioRF symposium today. (2/)
Based on cerebrospinal fluid cytokines, we identified two clusters of ME/CFS patients. Cluster 1 had elevated matrix metalloproteinases & many cytokines compared to cluster 2. Other than older age (Cluster 1), clinical presentation of these clusters was similar. (3/)
Published today📣
Our nasal booster in the "Prime & Spike" vaccine works without adjuvants (which are needed to induce adaptive immunity but also cause inflammation). @Kwon_Dongil @tianyangmao @BenIsraelow et al. asked how this is possible. (1/) nature.com/articles/s4159…
Prime & Spike is a vaccine strategy that leverages preexisting immunity primed by conventional vaccines to elicit mucosal IgA and T cell responses that prevent COVID infection and transmission in rodents. The nasal booster is simply the spike protein (2/) science.org/doi/10.1126/sc…
Our new study shows that the nasal spike protein booster converts lymph node memory B cells into IgA-secreting cells in the lung with the help of memory CD4 T cells. Ag-specific CD4 T cells replace all the necessary functions of adjuvants without nonspecific inflammation! (3/)
This prospective observational study led by @connorbgrady @bornali_27 @SilvaJ_C @hmkyale examined the impact of the primary COVID-19 vaccination on the symptoms and immune signatures of 16 people with #longCOVID. Here is what we found 👇🏼 (1/)
This study asked: Does COVID vaccination improve symptoms of long COVID? If so, is the improvement due to robust T and B cell responses leading to the clearance of the viral reservoir? If not, is there an immune feature that predicts worsening of LC? (2/)
The self-reported impact of vaccination was variable. Of the 16 long COVID patients, 10 felt better, 3 had no change, and 3 had worse health (1 hospitalized) 12 weeks after vaccination. Both physical and social effects of symptom burden appeared to decrease after vaccination. (3/)
Our preprint on post-vaccination syndrome is out. We studied immune signatures and examined spike protein in the blood of people who have developed chronic illnesses after COVID-19 vaccination. (1/) medrxiv.org/content/10.110…
Vaccines have saved countless lives and inspired me to become an immunologist. While generally safe, some people experience adverse effects, including Post-Vaccination Syndrome (PVS). Studying PVS is crucial for improving patient care and enhancing vaccine safety & acceptance. (2/) pubmed.ncbi.nlm.nih.gov/37986769/