2021年5月31日，世卫组织宣布使用希腊字母命名新冠病毒变异株。

据估计，一个人一生平均会感染10种不同病毒，包括流感病毒、冠状病毒、诺罗病毒和鼻病毒(Science 2015 348:aaa0698)

alpha，是在英国首先发现的B.1.1.7变异株，从变异株Alpha（B.1.1.7）到Beta（B.1.351），再到Gamma（P.1）和Delta（ B.1.617.2），SARS-CoV-2受体结合区域相当多的突变增强了与ACE2结合的能力，提高了病

毒侵入细胞的效率。因此，每次变异，新冠病毒都携带着更强的传播力。

Figure 1. SARS-CoV-2病毒进入的机制.

J Biol Chem. 2020 Sep 11; 295(37): 12910–12934.

Figure 2  SARS-CoV-2病毒进入的机制

J Pathog. 2020; 2020: 9238696.

Fig. 3  冠状病毒与生命周期

Nat Rev Microbiol. 2020 Oct 28 : 1–16.

Figure 4  SARS-CoV-2病毒颗粒：显示结构蛋白：S（蓝色）、E（棕橙色）、

M（红色）和N（粉色）

Viruses. 2020 Oct; 12(10): 1092.

Fig. 5  SARS-CoV-2的生命周期

Immunobiology. 2020 Nov; 225(6): 152008.

Figure 6  SARS-CoV-2的生命周期

Ann Transl Med. 2020 Dec; 8(24): 1686.

Figure 7  Coronaviruses engage with a host cell-surface receptor and deposit their RNA genomes into the host 

cytoplasm through endocytosis or directmembrane fusion (1). The positive-sense RNA genome is translated by 

the host translation machinery (2) to make polyproteins that are cotranslationally cleaved by proteases encoded

 in the polyprotein to generate components of RdRp complex (3). The RdRp complex uses the genome as a

 template to generate negative-sense subgenome and genome-length RNAs (4), which are in turn used as t

emplates for synthesis of positive-sense full-length progeny genomes and subgenomic mRNAs (5). Transcription 

and replication occur in convoluted membranes (CM) adjacent to DMVs that are both derived from rough endoplasmic

 reticulum(see Fig. 6 for more details). The subgenomic mRNAs are translated into structural and accessory proteins (6). 

The positive sense genomic RNA is bound by nucleocapsid and buds into the ERGIC, which is decorated with structural

 proteins S, E, and M translated from positive-sense subgenomic RNAs (steps 6 and 7). The enveloped virion is then 

exported from the cell by exocytosis (steps 8 and 9).

J Biol Chem. 2020 Sep 11; 295(37): 12910–12934.

Figure 8  SARS-CoV-2的生命周期

Int J Mol Med. 2021 Jan; 47(1): 3–22.

Fig. 9  SARS-CoV-2在宿主细胞内的感染周期

J Mol Biol. 2021 Jan 22; 433(2): 166725.