<story><title>Cuba′s Covid vaccine rivals Pfizer, Moderna</title><url>https://www.dw.com/en/cubas-covid-vaccine-rivals-biontech-pfizer-moderna/a-58052365</url></story><parent_chain><item><author>noveltyaccount</author><text>I was reading about the mRNA approach recently and wondered why not just inject the spike protein itself? Why have our body make the protein instead? Does anyone here know? It&amp;#x27;s interesting to see that both approaches yield such good results, and the end result, triggering immune response to the spike, seems about the same.</text></item><item><author>superkuh</author><text>Excellent news but there&amp;#x27;s a translation error or misunderstanding in this article.&lt;p&gt;&amp;gt; The scientists are using yeast as a receptor-binding domain.&lt;p&gt;I think they must mean they&amp;#x27;re using yeast as the protein expression medium and encode the receptor binding domain of the spike protein (along with the rest of the spike?) with yeast-y promoters and base sequence preferences. I guess there&amp;#x27;s nothing on the spike protein that needs to be glycosylated so non-mammal cell culture works.</text></item></parent_chain><comment><author>tzs</author><text>When the mRNA vaccine is injected into your arm muscles some of it ends up in the cells of the muscle and some of it ends up in the intercellular fluid. The latter drains via the lymphatic system and will end up in the lymph nodes in the upper body on the side you got the shot it (which is a good place to end up since the lymph nodes are a major site for immune response). Some will end up in the blood, and so might end up elsewhere.&lt;p&gt;Whatever cells it ends up in, the mRNA has them make the spike protein. That spike protein ends up attached to the outside surface of the cell that made it &lt;i&gt;and it stays there&lt;/i&gt; [1].&lt;p&gt;If you injected spike protein directly, it could end up anywhere. I don&amp;#x27;t know if this has been tested in humans yet, but there has been research in mice where spike protein injected damaged their lungs [2].&lt;p&gt;[1] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;blogs.sciencemag.org&amp;#x2F;pipeline&amp;#x2F;archives&amp;#x2F;2021&amp;#x2F;05&amp;#x2F;04&amp;#x2F;spike-protein-behavior&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;blogs.sciencemag.org&amp;#x2F;pipeline&amp;#x2F;archives&amp;#x2F;2021&amp;#x2F;05&amp;#x2F;04&amp;#x2F;sp...&lt;/a&gt;&lt;p&gt;[2] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.contagionlive.com&amp;#x2F;view&amp;#x2F;spike-protein-of-sars-cov-2-virus-alone-can-cause-damage-to-lungs&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.contagionlive.com&amp;#x2F;view&amp;#x2F;spike-protein-of-sars-cov...&lt;/a&gt;</text></comment>
<story><title>Cuba′s Covid vaccine rivals Pfizer, Moderna</title><url>https://www.dw.com/en/cubas-covid-vaccine-rivals-biontech-pfizer-moderna/a-58052365</url></story><parent_chain><item><author>noveltyaccount</author><text>I was reading about the mRNA approach recently and wondered why not just inject the spike protein itself? Why have our body make the protein instead? Does anyone here know? It&amp;#x27;s interesting to see that both approaches yield such good results, and the end result, triggering immune response to the spike, seems about the same.</text></item><item><author>superkuh</author><text>Excellent news but there&amp;#x27;s a translation error or misunderstanding in this article.&lt;p&gt;&amp;gt; The scientists are using yeast as a receptor-binding domain.&lt;p&gt;I think they must mean they&amp;#x27;re using yeast as the protein expression medium and encode the receptor binding domain of the spike protein (along with the rest of the spike?) with yeast-y promoters and base sequence preferences. I guess there&amp;#x27;s nothing on the spike protein that needs to be glycosylated so non-mammal cell culture works.</text></item></parent_chain><comment><author>superkuh</author><text>It boils down to the mRNA process being faster and more of a &lt;i&gt;sure thing&lt;/i&gt; for a novel virus. I hope there are eventually many more effective protein based vaccines approved.&lt;p&gt;The problem with expressing your protein in some animal cell is that often times there are sugars that cells add to proteins and they differ by lifeform type. So the protein will end up shaped different in a yeast than in a animal cell. Additionally, growing in a third party host lifeform often leads to situations where you can&amp;#x27;t get it to grow in the host anymore because the virus changes.</text></comment>