表达CD32的细胞系对CD8杀伤有作用吗？

文献原文：CD32-expressing murine fibroblast L cells were gifted to D.A.R. by M. Levings. CD32-expressing L cells between passage numbers 4 and 20 were incubated with an agonist anti-CD3 antibody (OKT3, Bio X Cell) for 30 min on ice and then plated with sorted CD8 T cells at a ratio of 5:1 CD8 T cells:L cells.（PMID: 37506196.）

我百思不得其解的两个问题：

1. 这里为什么要用表达CD32的细胞系与CD8共培进行杀伤实验呢？文章对CD32也没有特殊研究目的，CD32的表达也对CD8的杀伤起不到作用吧？如果有的话请大家赐教。

2. anti-CD3 antibody有什么作用呢？文章引用的另一篇文献PMID: 36470208也提到了这个